How Food Works. The Facts Visually Explained ( PDFDrive )

148 149TYPES OF FOOD Alternative foods New foods COULD WE USE FIBER AS FOOD? Any new food needs certain characteristics if it is to become a practical addition to the human diet: it must be safe, a good Although we cannot digest source of nutrients, economic to produce, and, ideally, have fiber, scientists have found a small ecological footprint. A good starting point is to try to a way to convert cellulose adapt existing foods, such as lupin beans and algae, although (a major component of fiber) scientists are also trying to grow meat from into starch that we can digest animal muscle (see below). and so could potentially Algal flour be used as food. Lupin plant Lupin bean Algae Lupin beans 20,000 Large algae—seaweeds—are Lupin beans are already part of popular food items in Asia, but some cuisines but they have also THE NUMBER OF EDIBLE some microscopic algae have also been used as the raw material to PLANT SPECIES WORLDWIDE been cultivated and used to make produce synthetic vegetable protein foods such as algal flour. foods, such as lupin meat and flour. Stem cell Sheet of on scaffold cultured meat BIOREACTOR BIOREACTOR Scaffold for stem cells Nutrient medium Final cultured meat product 3 Stem cells placed on scaffolds 4 Cultured meat produced 5 Cultured meat processed The stem cells are placed on frames Bathed in a nutrient liquid in the The thin sheets of meat are removed called scaffolds so that they have a surface bioreactor, the cells grow into sheets of from the bioreactor and processed into on which to grow. The scaffolds, which meat. The sheets are very thin (about thicker slices. Additives, such as colorings, are biodegradable and edible, are then 1mm/0.04 inches) and need processing flavourings, and fat, are mixed in to make the placed in a bioreactor. into larger, edible pieces. meat look and taste like natural meat.



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Drinking water WHAT ARE ELECTROLYTES? Clean, safe water from the faucet is one of the great In food science, electrolytes achievements of civilization. Bottled water has refers to dissolved minerals become increasingly popular, but there are concerns or salts. The body needs about its environmental impact and no concrete electrolytes such as sodium, evidence that it has health benefits. potassium, and chloride for normal functioning of its Treatment of tap water Water tissues and cells. The purpose of water treatment agitator is to remove dirt, debris, toxic COAGULANTS chemicals, and microbes to produce water safe for human consumption. The details of the treatment process vary from region to region, depending on water standards, but it typically involves the stages shown here. 2 Coagulants added Chemicals, such as aluminum sulfate and iron chloride, are mixed into the water to make dissolved RESERVOIR particles come out of solution and clump together—or coagulate—with particles of dirt. 1 Water from source Larger clumps Water for human consumption is of particles drawn from lakes, rivers, reservoirs, and boreholes. It is screened to sieve out large debris and organic matter that would otherwise clog up later processing stages. SLUDGE LAYER Tap water 3 Settling Under gentle mixing, the In developed countries, tap water is thoroughly treated to remove coagulated particles cluster together dirt, microbes, and toxic contaminants. It is also rigorously tested to form large clumps, a process to ensure it remains safe to drink and cook with; in fact, the known as flocculation. These clumps testing may be to a higher standard than that for some bottled settle out to the bottom of the tank waters. In addition to ensuring safety, water treatment may also (sedimentation), where they form a include adjusting the acidity or alkalinity of the water, so that it layer of sludge that can be removed does not corrode pipes. Tap water may have certain substances and treated for use as fertilizer. added to improve health—for instance, fluoride to reduce tooth decay—but any such additives vary according to local regulations.

152 153DRINKS Drinking water Mineral water Bottled water Mineral waters were traditionally drunk at their Bottled water is not necessarily from a spring natural sources, such as spas or wells. Now, they are more commonly bottled at the source and distributed or other natural source. Many bottled waters for sale. They often have high levels of dissolved minerals, although these do not necessarily confer essentially come from the tap, and some are not health benefits, and they must have a consistent composition and be safe to treated in any way. Bottled water is typically sold drink without any treatment. Spring water also originates in plastic bottles, and there are concerns about from a natural source, but its composition may vary and it the environmental impact Less than 1% may be filtered or treated. of the packaging: the treatment at plant bottles need a lot of energy and other Less than 1% resources to make, filling, labeling, and they also create and sealing bottle a lot of waste. 4% refrigeration Mineral-rich water SPA WATER Energy in a bottle 45% from natural spring FOUNTAIN Only a fraction of the energy transportation cost of producing water in a Spa water plastic bottle comes from 50% production Many spas historically developed around treating and bottling the water. of plastic bottle natural springs, where the mineral water was The vast majority is used in believed to be beneficial for health, both making the bottle and when drunk and also when bathed in. transporting it for sale. 4 Filtration 35BILLION The water is then passed through beds of increasingly fine THE NUMBER OF PLASTIC gravel, sand, and charcoal to WATER BOTTLES THROWN IMPURE WATER remove remaining particles AWAY EVERY YEAR IN THE and microbes. US ALONE Fine gravel Sand PARTICLE 5 Disinfection and storage FILTER Chemicals are added to Charcoal CLEAN WATER the water to make sure it is not acid or alkaline and to destroy any remaining microbes. The water is 6 Public water supply then stored, ready for distribution. Water is distributed to homes and businesses through public water pipes. Water that will pass through lead pipes sometimes has additives that prevent lead from leaching into the water. ADDITIVES DISINFECTANTS STORAGE TANK DRINKING WATER

WHAT’S THE 1 Harvesting DIFFERENCE When a coffee plant is five BETWEEN ARABICA AND years old or more, its berries can be ROBUSTA COFFEE? harvested. They are picked when they have ripened from green to red. Arabica has a more delicate, sweeter flavor and is slower COFFEE PLANT growing—and so, more expensive—than robusta, which has twice the caffeine. From berry to bean 2 Processing The ripe berries are processed Coffee is an infusion of ground, roasted to remove the outer skin, pulp, and beans that come from inside the berries parchment. The end result is raw of shrubs belonging to the Coffea group of green beans. plants. Once the berries have ripened on the bush, they are picked and the pulpy Parchment flesh must be removed from the beans within. Sometimes they are left to dry and ferment in the sun before the pulp is removed; another method is to remove most of the pulp first and then ferment the bean. They are then washed and dried. Bean BEANS PROCESSED Pulp Coffee 3 Roasting The green beans are roasted Every day, more than two billion (typically in a large drum) to bring cups of coffee are drunk by people out the characteristic coffee aroma all around the world. It is valued and taste. for its stimulant properties, and for its complex flavors and aromas. DRUM ROASTING

154 155DRINKS Coffee How much caffeine? Espr Bre wed decaffeina ino Espresso Caffeine on the menu On 8fl oz ted ated The longer coffee is brewed, the more Although tea leaves contain 1fl oz caffeine is extracted. The espresso more caffeine than coffee beans (240ml) (30ml) method forces hot water through (2–3 percent against 1–2 percent), 2–12mg 47–75mg grounds at high pressure, mobilizing in brewing, much more caffeine is the volatile, flavorful oils without extracted from coffee than from tea. esso decaffein e-shot cappucc extracting as much caffeine. A typical cup of coffee may contain 1fl oz 8fl oz about 50–100mg of caffeine, compared (30ml) Brewed to 20–50mg for a cup of tea. Different (240ml) methods of brewing can radically 0–15mg 47–75mg 8fl oz alter the amount of caffeine that (240ml) is extracted from ground coffee. LOW 95–200mg 10 MILLION TONS 8fl oz CAFFEINE HIGH OF COFFEE WERE (240ml) PRODUCED IN 2015 tant2d–1e2cmafgfeinat 8fl oz (240ml) Ins ed 27–173mg Instant HOW CAFFEINE AFFECTS THE BODY How instant BREWED coffee is made COFFEE Caffeine is the most widely consumed psychoactive Instant coffee is coffee that FREEZER AND substance (one that alters mental processes) in the has been brewed and then GRANULATOR world. The most notable effects of caffeine occur dried to a powder so that it after consumption of low-to-moderate amounts can be reconstituted simply (50–300mg—the recommended daily limit is 400mg). by adding water. There are They include increased alertness, energy, and ability two methods for doing this: to concentrate. Large amounts can lead to negative either the liquid coffee is effects, such as anxiety and insomnia. sprayed into a hot, dry atmosphere through a tiny Brain Stomach nozzle to give a superfine VACUUM Water Relieves fatigue; Excessive mist, which quickly dries into CHAMBER drawn out consumption powder, or liquid coffee is of frozen can lead to linked to frozen and then freeze-dried, coffee anxiety or heartburn with the water turning granules insomnia directly from ice to gas. Heart and Kidneys Freeze-dried coffee circulation Diuretic; All types of instant coffee lose Raises blood increases risk flavor and caffeine during of kidney manufacture, but freeze- pressure; stones drying preserves more of increased risk the aroma compounds. of irregular heartbeat INSTANT COFFEE GRANULES

Tea DOES TEA HAVE LESS CAFFEINE The world’s most popular brew has a rich history, stretching back thousands of years, THAN COFFEE? and an equally rich store of nutrients. There are many types of tea, from black to white. Although tea has a higher caffeine content than coffee, The main varieties WHITE usually less makes it into the tea Tea varieties are determined by the infusion—50mg per cup of tea maturity of the leaves when picked, and the degree and duration of compared to 175mg their processing. per cup of coffee. MYpaEatraLuolnlLrolelfhOewifrldedeeeeWarraddaimtven,itnedldeoigsgnsd,pahotarartaminelreyftdtdeiea,tmrlhlyeonre. Buds or young occnaueofnrnirdfszee,sMydrdtthmmeratieaoeeetmnudnsdr,r.teeeosadGoatllliecoeotRathdrnivvEapeatEastneNare HERBAL TEAS leaves are steamed Herbal teas are made from to deactivate the infusion of herbs, spices, enzymes and or fruit extracts in hot water. prevent more than To distinguish it from a light fermentation, “true” tea, a herbal tea may also be referred to as a then dried. tisane, or infusion. Taken hot or cold, they do not ABfmtuaeLrlaaalAeyt,nuswmCfdere(eivKoarltfeemhdrlierrfeeotaieanrlxtnfvegorhietddoeoasf,imedznurtrehodrm)salldftebeordnerytfionrge. OOLONG thhueofenaurtdgminehAlergitgfknleoasoetoanraey,dltksoepinoslrnuloeonoPg-clwewelaUoirrnfnhn.tt-geedaEt,aresaR,ardy,Hark contain caffeine. Said to be semi- fermented, this tea is made from withered mature leaves that are bruised and fermented for a short time, before being pan fired and dried. Types of tea 38 Tea most commonly refers to an infusion of dried PERCENT OF TEA leaves of a camellia bush (Camellia sinensis, not the IS GROWN IN CHINA, garden variety). The basic preparation of dried mature THE LARGEST PRODUCER leaves is green tea. Freeing enzymes in the cells of the OF TEA IN THE WORLD tea leaves produces darker teas, transforming simple phenols into more complex ones—a process commonly but mistakenly called fermentation.

156 157DRINKS Tea What is in a cup of tea? F VITAMINS Green tea Green tea is rich in colorless, Polyphenol CHINSSAPONINRelaxant amino bitter, but not astringent flavonoids are Foaming, contains vitamin C acid with strong phenols called catechins. thought to have Santimicrobialand B2, along with In the production of black antioxidant andLAVONOIDS agents, said to umami and tea, enzymes released during immune-boosting lower blood folic acid and sweetness flavor rolling and bruising of the pressure and fight water-insoluble characteristics leaves and oxidation convert properties tooth decay THEANINE most of the catechins into vitamin E theaflavins, which give black tea its slightly bitter, astringent Rich in CATE flavor. Tea also contains caffeine, potassium, theanine, flavonoids, saponins, calcium, vitamins, and minerals. phosphorus and XANTHINE DERIVATIVES The most magnesium, and prevalent types of Green tea phenol flavonoids in The color of green tea comes from other trace Caffeine and green tea; may be the chlorophyll in the leaves. This is minerals other xanthine- anticarcinogenic preserved because the leaves undergo MINERALS derivatives, such as little processing, and it is not masked theobromine, are by dark phenols. stimulants Water, steeping times, HERBAL °C BLACK Cooling down and temperatures 3–5 mins 100 °F GREEN A hot drink can actually Brewing the perfect cup of tea 90 220 help you to cool down on is an art and a science. The final 1–2 mins 80 2–3 mins a hot day, by increasing the brew should be slightly acidic— YELLOW 70 amount you sweat. Although with a pH close to 5—so it is best 200 the drink raises your core to start with water that is neutral, temperature, the net effect and with a moderate mineral 190 OOLONG is heat loss. content. Mineral water may be better suited than tap water in 180 More sweat Core body 2–3 mins produced temperature many regions. While larger on skin increased flavor compounds 170 emerge slowly, and at higher WHITE temperatures, 160 in green tea, cooler water limits the extraction of bitter and astringent compounds. Optimum conditions 3–6 mins 1–2 mins Different types of tea are best prepared using particular water temperatures and brewing times.

Fruit juice and GRAPE FRU IT PU RE JUICE smoothies 32 grapes Juice of One of the hottest diet fads is the 0.5oz/15g 64 grapes extracting and blending of healthy 1.27oz/36g ingredients to make easy-to-consume drinks. Although juices and smoothies have much to recommend them, the hype masks some potential downsides. Fruit and vegetables versus juice ORANGE 1 orange Juice of 3 oranges 0.4oz/12g 0.75oz/21g While juice is often touted as offering the health benefits of fruit and vegetables, in fact, juices differ PINEAPPLE 1 slice Juice of 3 slices significantly from the whole foods from which they are 0.25oz/8g 1oz/28g made. In addition to removing the beneficial insoluble fiber from fruit and vegetables, juicing removes their texture and, especially in vegetables, strips away the structure that can actually have a cleansing action on teeth. In fruit juice, all the sugar from a large amount of fruit is concentrated into a much smaller volume, resulting in a very high sugar content. The sugars are liberated and immediately available to bacteria in the mouth that contribute to tooth decay. Solid or liquid? KEY GRAPEFRUIT Half a grapefruit Juice of 1 grapefruit A small glass of orange juice contains Portion of 0.3oz/9g 0.6oz/18g almost all the fruit sugar (fructose) of fruit eaten three medium-sized oranges—more whole oranges than most people would eat. Furthermore, it contains only a very Portion of small fraction of the fiber content. fruit in a glass of juice IS FRESHLY Sugar (oz/g) SQUEEZED JUICE BETTER THAN JUICE FROM APPLE 1 apple Juice of 3 apples CONCENTRATE? 0.6oz/18g 0.85oz/24g There is no difference in the POMEGRANATE Half a pomegranate Juice of 2 pomegranates nutritional value of juice from 0.4oz/12g 1.1oz/32g concentrate. If sugar has been added, however, it will raise calories and the risk of tooth decay.

158 159DRINKS Fruit juice and smoothies More nitrates Smoothies Sugar spike Green smoothies are high in Blending ingredients increases nitrates, which can help to their glycemic index, meaning that the body absorbs their dilate the body’s blood vessels and reduce sugars more quickly. Adding blood pressure. greens to smoothies can counteract this. More fruit and Smoothies are blended vegetables Smoothies can whole ingredients, often help us to meet the five-a-day promoted as health foods, because target of fruit and vegetables, but are unlike juices, they retain the fiber of better used as a complement rather than the whole food. In practice, there are to replace whole PROS nutritional pros and cons. On the one hand, CONS Tooth decay meals. they can encourage the intake of fruits and A flood of fruit sugars and More vegetables, and blending can help to break the lack of beneficial texture down cell walls, releasing more nutrients. increase the risk of tooth phytochemicals Using whole fruit On the other hand, they can lead to the decay. Rinsing your mouth and vegetables in rapid intake of large amounts of with water can help a smoothie helps you avoid this. to boost fiber intake and that of sugar. Store-bought smoothies phytochemicals attached may even contain Kidney added sugar. stones to fiber. Green Smoothie sense smoothies The faults in smoothies can be can be high in counteracted by the way you make compounds them. Adding greens, such as spinach called oxalates, or celery, can not only accentuate the which increase benefits, but also reduce the drawbacks, the risk of kidney such as blood-sugar spikes. stone formation. Fruit juice versus 12 0.12 BLENDED SOUPS soft drinks Sugar content (g/100ml) 8 0.08 Sugar content (oz/fl oz) At least one study backs up the Fruit juices may not be claim that soups can fill you up much healthier than soft 4 0.04 more than solid foods taken with drinks or energy drinks. They water. This implies that blended contain comparable levels of soups stay in the stomach longer, sugar and can take daily sugar inhibiting the release of ghrelin, intake to levels that contribute the “hunger hormone,” so that to obesity and diabetes, appetite is suppressed. especially in children. 00 Sugar content of drinks Energy Soda Orange Energy drinks can contain amazing drink juice quantities of sugar. While a typical can of soda contains around seven spoonfuls, orange juice is not that far behind.

Carbonated drinks Additives ADDITIVES 3% ANTIOXIDANTS The additives in sodas PRESERVATIVES Many people enjoy carbonated drinks as a regular are mainly colorings and COLORINGS part of their diet. Although they are mostly water, flavorings, but also acids (citric FLAVORINGS they contain a significant quantity of sugar and have and phosphoric acid) to add ACIDS been implicated in a number of health problems. “sharpness,” preservatives, EMULSIFIERS emulsifiers, and antioxidants. What is in soda? Typically, a carbonated drink starts as a “simple syrup” of sugar and water. The other ingredients are then added in a specific order to give what is called the “finished syrup.” This is diluted with water, carbonated, and bottled (or canned). For some bottled drinks, carbonation is done after bottling, just before the bottle is sealed. Under pressure Putting the fizz in a drink is achieved by bubbling carbon dioxide gas through the liquid under high pressure, so that the carbon dioxide dissolves. When the pressure is released, the carbon dioxide forms gas bubbles again. KEY Bottle When bottle is opened, SUGAR 7–12% cap keeps carbon dioxide forms Carbon pressure bubbles of gas Sugar dioxide on dissolved A typical soda contains up to (CO2) carbon TONGUE 12 percent sugar. In a 11 fl oz dioxide (330 ml) can of regular soda, this Water in water Carbon dioxide equates to about nine (H2O) bubbles burst teaspoons of sugar. In on tongue diet soda, some or all of the sugar is replaced with sweeteners. Containing the fizz Feeling the fizz The carbon dioxide remains dissolved because Opening the bottle releases the pressure, allowing it is kept under pressure. Some of the dissolved the carbon dioxide to become a gas again. carbon dioxide forms carbonic acid. Carbonic acid in the liquid gives a “sharp” taste.

Supersizing drinks WATER 85% The introduction of cheap sugar alternatives in the 1970s led to an Water increasing supersizing of soft drinks. Previously, drinks came in Water makes up most of a 6.5fl oz (190mL) bottles, but the standard can now contains 110fl oz soft drink. Usually taken from (330mL). As a result, people are often consuming significantly the city water supply, the more calories in drinks than they could possibly eat. water is filtered and treated to remove solid Movie theater-sized Butter not particles and microbes portion is equivalent to included in before adding sugar three standard cans calories and additives. After this, the liquid is LARGE SIZE 2 BAKED POTATOES carbonated. CARBONATED 5oz (200g) DRINK 32fl oz (940mL) 364 CALORIES 376 CALORIES TRUCKS TRANSPORTING DRINKS SODA HAVE TO DISPLAY THE HAZARD WARNING SYMBOL Carbonated 160 161drinks FOR HIGHLY CORROSIVE MATERIAL Rotting the teeth Tooth staining and decay TOXIC TONICS The sugar in soda contributes It is not only the sugar in sodas to the buildup of plaque, which Sodas began as health tonics, based on the that is bad for you; they also can lead to staining and decay. widespread belief that carbonated spa contain three acids—citric, waters were healthy. Cola drinks began carbonic, and phosphoric. These as a mixture of wine and cocaine until all have an average pH of 2.5, Prohibition in 1886, when the wine was which is slightly stronger than replaced by soda water. Cocaine remained stomach acid. These acids erode until 1904, when its addictive qualities the enamel of teeth, exposing became a matter of concern. them to microbial attack and subsequent decay.

Energy drinks CAN PROTEIN Manufacturers’ claims have driven the explosive SHAKES REPLACE growth of the energy drink market. Positioned at the MEALS? intersection between soft drinks and supplements, energy drinks struggle to back up their boasts. Protein shakes can be an effective meal replacement as part of a balanced diet, but Types of energy drinks they lack the essential vitamins and minerals of a Energy drinks are soft drinks that claim to boost energy levels. They usually have high levels of caffeine and sugar, and may contain electrolytes complete meal. (mineral ions, such as sodium, normally dissolved in the blood). Many feature amino acids, herbal extracts, and other ingredients claimed to have health benefits. The market has diversified to include sugar-free varieties and concentrated versions in the form of shots and gels. Drinking them with alcohol increases the risk of overindulgence and dehydration. GUARANA SEEDS HAVE TWICE AS MUCH CAFFEINE AS COFFEE BEANS The verdict ENERGY DRINK Real benefits? SPORTS DRINK Packed with caffeine Sports drinks differ and usually full of Main ingredients: in electrolyte levels Main ingredients: sugar, energy drinks Stimulants formulated for Electrolytes are not regulated. Sugar before, during, Sugar They can contain Water and after exercise. Water 200 milligrams or However, other than more of caffeine Effects and drawbacks endurance athletes, Claimed benefits per serving (a very Simple sugars can give an people are unlikely Formulated to replace strong cup of coffee immediate surge in blood to run low on electrolytes lost in sweat, might contain 180 sugar levels and caffeine can electrolytes or and replenish energy stores milligrams), and may mask feelings of fatigue, but exhaust energy depleted by long exercise, contain as many as any energy-boosting effects stores, so sports sports drinks are supposed to 400 calories. are short-lived and typically drinks rarely improve stamina and prevent precede a crash. Negative perform better athletes from exhausting impacts include weight gain, than water. their carbohydrate-based headaches, and anxiety. energy stores.

162 163DRINKS Energy drinks Stimulating the body CAFFEINE AND SPORTS Energy drinks often contain Guarana Caffeine can increase Brain caffeine, taurine, guarana, Seeds of the guarana muscle endurance and Heart ephedrine (restricted in some plant contain more speeds up the production countries), or ginseng—all caffeine than coffee of glycogen—the body’s Muscle included as stimulants. Caffeine beans, but supposedly carbohydrate energy works by stimulating adrenaline release it more slowly. store. High adrenaline release and by blocking the They also contain cardiac levels boost blood flow “fatigue” signal produced by stimulants theobromine to the heart and muscles adenosine—a chemical made and theophylline. and stimulate energy when the body's metabolism production. Adrenaline releases energy. Ephedrine is may also reduce also a stimulant but one with perceived levels of dangerous side-effects including pain and fatigue. high blood pressure and heartbeat irregularities. Do they work? PROTEIN SHAKE Conclusion ENERGY GEL Designed to help As with sports build muscle mass, Main ingredients: drinks, gels are Main ingredients: protein shakes Protein powder unlikely to benefit Electrolytes provide the amino Flavorings anyone other than Amino acids acids necessary to Sweeteners endurance athletes, Additives build up muscles. such as marathon In reality, only What is on offer runners. For Product breakdown high-level body- Protein shakes are drinks everyone else, they Highly concentrated into builders need more made from protein-rich provide empty syrupy gels, these provide than can easily be supplements, most often calories, with portable forms of energy obtained in the diet. from whey (milk proteins left implications for supplement, intended for Excessive levels of behind by cheese making), weight gain and endurance athletes on the go protein may cause but also from casein in milk, diabetes risk. who need to minimize the kidney damage and soy, egg, hemp, rice, and pea. weight they are carrying. They bone loss. They are high in calories. may also contain caffeine and other stimulants.

Alcohol IS ALCOHOL A POISON? All alcoholic drinks contain ethanol—the chemical name for the simplest form of alcohol. Most forms In sufficient amounts, alcohol of alcohol are made by fermenting grains (for beer, see slows down brain function, pp.172–73) or grapes (for wine, see pp.170–71). More irritates the stomach, pure forms of alcohol are produced by distillation. dehydrates you, and lowers your body temperature and blood sugar levels. So yes, it is a poison. 2 Evaporating alcohol 3 Condensing Ethanol boils at 173ºF In the pot distillation process, the Volatile compounds (78.4ºC) so it evaporates, different components such as ethanol leaving water behind. Other evaporate chemicals in the mix, including condense as the evaporate passes through a system highly toxic methanol, are also of cooling pipes. volatile so evaporate, too. BOILER Cooling pipe CONDENSER Distillation Distillate collects Alcohol is made initially through the 4 Distillate Methanol fermentation of sugary plant juices. The distiller This lightest of alcohols Distillation is used to produce a more must draw off and comes off first. Distillers pure form of alcohol. The various discard lighter volatile throw this away because components of a mixture boil at different compounds (congeners), it is poisonous. temperatures, so as the mix is heated, which pass through Ethanol some components boil off before others. the condenser first. In The principle alcohol If these can be captured and condensed small quantities, these in all alcoholic drinks. separately, it is possible to obtain alcohol congeners provide flavor. of 95–98 percent purity. Butanol This gives some spirits The distillate is diluted their oily nature, as its for consumption (see structure is similar to pp.166–67). those of fatty acids. 1 Heating the ferment COLLECTING VESSEL Grapes (to produce brandy, for example) or grain (to make whiskey) are first fermented to produce alcohol. Once the fermentation has finished, the ferment is heated inside the distillation plant or still.

164 165DRINKS Alcohol How much in a drink? Calorie count At 7 calories per gram, alcohol contains almost as many Guidelines as to what counts as moderate calories as pure fat. Most drinks contain sugars, too, which drinking, and particularly what constitutes add to the calorie count. The drinks below each contain a standard drink, vary by country. In the US, 0.6fl oz (14g) alcohol—a standard US drink. one standard drink contains 0.6fl oz (14g) of alcohol, while in Austria it is 0.3fl oz (6g) and PURE 5fl oz (150ml) in Japan 0.85fl oz (19.75g). In the UK, official ALCOHOL 12% alcohol guidelines refer to units (one unit is about 125 calories 0.35fl oz, or 8g, of alcohol). 12fl oz (355ml) Many of the calories Red wine can be up 5% alcohol in beer come from to 16% alcohol, and 155 calories unfermented sugars even more calories 1.5fl oz (44ml) 6.5fl oz (192ml) 40% alcohol 5% alcohol 95 calories 150 calories Alcohol and calorie content depends on the ratio of alcohol to mixer BEER SPIRITS WINE SPIRITS AND MIXER Is alcohol ever healthy? RISK OF STROKE There is a paradox around alcohol and health. Alcohol increases the risk of liver disease and a range of cancers, but studies have shown a correlation between moderate alcohol consumption and improved heart health. Some experts are sceptical, others point to beneficial effects of antioxidants or nitrous oxide boosting blood flow. There may even be a link to less anxiety and more sociability, with associated health benefits. MODERATE ALCOHOL 012 3 4 5 67 INTAKE MAY REDUCE NUMBER OF DRINKS PER DAY STROKE RISK The case of stroke Small amounts of alcohol may have a protective effect on the heart. One study in 2007 showed how the risk of stroke (purple line) correlated with alcohol intake—with a moderate consumption having a protective effect. However, more recently other studies have raised doubts over this.

Spirits Ever since ancient and medieval pioneers first practiced the Distilled from a art of distillation, the production of spirits has been an fermented mash of the alchemical process capable of transforming base heart of agave plants (a ingredients into concentrated alcohol. kind of cactus), which are rich in fructose (fruit Spirit or liqueur? Spirits distilled from grape sugar) and inulin. Inulin wine. The two most famous is an indigestible chain Spirits are alcohol (ethanol) products made of fructose sugars and by the distillation of a fermented mash brandies—Cognac and (see p.164). While beer may contain as Armagnac, named after their is broken down by little as 3 percent alcohol by volume (ABV), French regions of origin—are steaming or roasting spirits have an alcohol content of more than 20 percent and are generally at least made from white wine. the agave hearts. 40 percent. A liqueur is a sweetened, and often flavored, spirit. Popular spirits Blue agave Spirits differ according to the source of their original is the species fermented sugars, as well as by the purity of the commonly used distillate before it is diluted. Coloured impurities in the distillate (congeners) provide flavor. in tequila ALCOHOL IS THE CAUSE Fermented OF 5 PERCENT OF ALL grape juice CANCERS WORLDWIDE yields brandy when distilled BRANDY TEQUILA Drinking dangers One extra case Although some data suggests one or two drinks a day can benefit NO ALCOHOL 10.5 UNITS PER WEEK ARE SPIRITS MORE heart health (see p.165), even HARMFUL THAN WINE moderate drinking could be a cause 22 UNITS PER WEEK Three extra of cancer. Alcohol has been linked lifetime cases OR BEER? with nine cancers, including mouth per 1,000 and throat, liver, breast, and bowel. people All forms of alcohol are The chief suspect is acetaldehyde, harmful, being broken down a breakdown product of alcohol. Eleven extra into toxic substances in the cases per 1,000 liver. Spirits are more strongly Mouth cancer Oral cancer cases increase with alcohol linked with mouth cancer, consumption (1 unit = 1/3fl oz, or 10ml, of pure especially in smokers. alcohol, or one modest drink). When it comes to cancer, there is no safe drinking limit. 44 UNITS PER WEEK

166 167DRINKS Spirits Traditionally made Whiskey is essentially Originating from the cheapest made from beer, in by-products of the sugar industry starch source without the hops, since in the Caribbean, available, vodka is it is distilled from rums are distilled usually made from fermented grain— from fermented grain but also from molasses. Light rum mainly barley, corn, rye, is distilled to a high potatoes and or wheat. Barrel-aging purity, but dark sugarbeet. The source rums retain more contributes to the is less important character of the flavorful because the spirit is finished drink. congeners. distilled to great purity, excluding most aromatics. Some traditional Malted barley (barley Sugarcane juice vodkas are still that has sprouted and is the source of made from begun releasing its molasses for rum fermented potatoes sugar—maltose) is the starting point Most vodka is for many whiskeys made from grain VODKA WHISKEY RUM Alcohol abuse EXPLOITING DENSITY Alcohol and its breakdown products CIRRHOTIC The strongest, most COINTREAU (such as acetaldehyde) are toxic LIVER alcoholic drinks float IRISH CREAM to many different organs and on water, since water tissues of the body. Long-term Lumps of fibrous is denser than ethanol. LIQUEUR overuse of alcohol over a decade scar tissue Heavier ingredients, COFFEE or more can damage most however, such as coffee, LIQUEUR systems of the body and seriously Liver damage make most drinks increase the risk of cancer (see Alcoholic cirrhosis of the liver heavier than water. B-52 SHOT opposite), liver disease, stroke, is where alcohol breakdown Skilled bartenders heart disease, brain damage, products damage the liver, exploit different drink neurological damage, depression, causing it to regrow with scar densities to create seizures, gout, pancreatitis, and tissue and fatty deposits that layered cocktails. anemia. In all, over 60 diseases limit its ability to function. have been linked to alcohol abuse. Cirrhosis can be fatal.

Alcohol and the body Alcohol gets into the body very fast. Unlike Genes and alcohol most food and drink, it is absorbed into the bloodstream within minutes. It takes the liver Some ethnic groups have genetic about one hour to process one unit of alcohol, variations that prolong the endurance forming a highly toxic compound as it breaks of acetaldehyde in the body. This can it down for elimination. cause unpleasant nausea and flushing, but may also have the effect of putting Effects of alcohol on the body them off drinking. Genetics can also play a part in whether someone is As alcohol hits the stomach, around 20 percent begins to cross predisposed to become an alcoholic. into the bloodstream right away. It is quickly passed to the liver, brain, and pancreas, where it starts to break down. The Red flush rest is absorbed through the gut. Alcohol is first broken down into acetaldehyde, then acetate, and is finally eliminated as carbon dioxide and water. Acetaldehyde is highly toxic and causes damage to cells, especially those of the liver, which can become irreparably damaged. MOUTH STOMACH CIRCULATORY SYSTEM LIVER Warm feelings Fatty liver Taking it in Upset stomach Alcohol makes the blood vessels Repeated use leads to Contact with strong alcohol Alcohol stimulates the stomach widen, making you feel warm. It inflammation and scarring of can damage the cells lining the to produce large quantities of also causes a temporary drop in liver cells. Fat becomes deposited mouth, throat, and esophagus, acid that can irritate the lining blood pressure and pulse rate. between the cells, making it hard promoting cancers in these areas, of the stomach and lead to Small vessels can also break. for the liver to work properly. especially among smokers. ulcers over time. Under the influence IT TAKES ABOUT THREE Alcohol is a psychoactive drug. HOURS FOR YOUR BODY In small doses it acts as a depressant, TO BREAK DOWN THE but reduces inhibitions and anxiety ALCOHOL IN A LARGE to produce feelings of euphoria. (8.5 FL OZ/250 ML) At higher doses it causes intoxication, GLASS OF WINE stupor, and unconsciousness.

168 169DRINKS Alcohol and the body 0.03g/mL BLOOD 0.08g/mL BLOOD 0.2g/mL BLOOD 0.3+g/mL BLOOD Alcohol—the backlash Mood picks up, Judgment, vision, Loss of motor Acute risk of balance, and speech Hangovers only start after inhibitions disappear, start to be affected control and mental alcohol poisoning feel euphoric function and death all the alcohol has been metabolized. Typical symptoms include tiredness, dizzyness, nausea, and headache and can last for 24 hours. Dehydration is 0 0.1 0.2 0.3 often blamed for the HIGH effects, but the real Hand-eye coordination culprits are thought affected to be congeners— BRANDY by-products of fermention that 0.12g/mL BLOOD 0.3g/mL BLOOD often give the drink RED WINE Bodily coordination May become unconscious— and judgment impaired its flavor and color. HANGOVER SEVERITY hospitalization required Some experts also RUM propose a theory Blood alcohol levels that hangovers may WHISKEY As you drink, the concentration of alcohol in your blood rises. This leads to an increasing loss be due to reactions of control of physical and mental faculties. of the immune WHITE WINE system. GIN VODKA BEER LOW KIDNEYS BRAIN LUNGS Dehydration Off your head Alcohol increases urine Some alcohol is broken down Breathing risks production as soon as 20 by the brain, which is instantly Drinking increases the risk of minutes after being drunk. affected. Control of mental and inhaling vomit and also affects Excess drinking can lead to physical functions becomes nitric oxide levels, both of which thirst and dehydration. progressively harder. make the lungs more susceptible to infection. WHY DOES CHAMPAGNE MAKE Alcoholism YOU DRUNK SO FAST? Overuse of alcohol can tip a social drinker into becoming The bubbles in champagne an alcoholic. The body helps the body absorb alcohol develops a physical tolerance to alcohol and it becomes into the bloodstream more psychologically difficult to quickly, as do carbonated stop drinking. Giving up produces withdrawal mixers with spirits. symptoms that can be as bad as those of drinking.

CRUSHER Fermentation vessel is warm, CHEMICALS IN WINE RED encouraging the release of GRAPES chemicals from the skins Procyanidins and seeds A kind of tannin that makes young reds bitter, procyanidins may act on artery 1 Grapes linings to improve cardiovascular health. crushed To release juice, Resveratrol grapes are first FERMENTING Warm fermentation This phytochemical has been shown in crushed and the TANK 2 Yeast ferments the crushed rodents to lower blood sugar and fight cancer (in high doses). stems removed. grapes, converting its sugar to alcohol. Winemakers may add a Flavonols The squashed cultured yeast, or they may rely Shown to have antioxidant and anti- grapes, with cancer actions in animals, although skins and seeds, on the yeast on the grape skins. the dose in red wine is very low. are poured out. PRESS Anthocyanins The human body metabolizes these antioxidants quickly, so if active, they must be effective in trace amounts. 3 Pulp pressed Richly colored press wine pours The crushed, fermented grapes from the press and is added to flow into the wine press, which applies the free-run juice to improve appearance and flavor pressure to release further color and flavor from the grapes. Wine from the fermenting tank, known as free-run Secret ingredients juice, is mixed with a little fluid from the press The red wine making process fills your glass with extracts of grape Is red wine better for you? skins and seeds. It is not clear which of these, if any, benefits Interest in the possible health benefits of moderate wine drinking human health. One chemical reached a high in the 1990s. It was then that US journalists noted that called resveratrol has a range the population of France was longer lived and more free of coronary heart of benefits in lab mice, but only disease than those of other countries with high-fat diets, such as the UK in doses impossible to achieve and US. Attention focused on red wine, because unlike white, it is made by by drinking wine. Procyanidins fermenting whole grapes, skins and all, and contains a range of chemicals in high-tannin wines might be such as tannins, flavonoids, and pigments called anthocyanins. Scientists more promising candidates. are still investigating the therapeutic actions of many of these. Wine In recent decades, wine has gained publicity for its potential benefits to health. Some experts claim a glass of red a day lowers the risk of heart disease and other cardiovascular problems. So what is it about wine that is healthy, and is red better?

CRUSHER WHY NOT Pulp contains RED OR JUST EAT GRAPES? juice, skins, WHITE GRAPES and seeds The supposedly beneficial 1 Grapes are crushed ingredients in red wine are also FERMENTING The white wine present in the skins and seeds of TANK process begins with crushing PRESS grapes to release the juice. the grapes we eat. However, many people prefer to 2 Grape pulp pressed eat seedless grapes, or The press separates avoid chewing the bitter seeds. the skins and seeds, which are discarded. Clear, filtered juice runs out of the press. Pure fermented 3 Cold fermentation Tannins and juice (white wine) The pure grape juice is cold-fermented antioxidants are filtered out with by yeast in vats or sealed barrels. The process the seeds and gives a fresh, juicy taste, without the bitterness skins before or astringency of tannins. fermentation WINE IS AN INGREDIENT IN THE OLDEST KNOWN RECIPES FOR MEDICINE, DOCUMENTED IN 2200 bce, ON PAPYRI IN EGYPT IT’S ONLY A GLASS A little of what you like Wine measures vary from place to 125 In white wine, the skins and seeds calories are removed before fermentation so place and according to trends, so it white lacks the phytochemicals of 200 red wine. However, experts are can be difficult to know that you calories learning that the health benefits of red wine may have been overstated, drinking in moderation. A large glass 600 and some studies find, paradoxically, calories that it is actually the alcohol in can be one-third of a 750ml (25fl oz) wine that is healthy (see pp.166–67). If true, white-wine drinkers could bottle, containing 200 calories, also benefit from a glass a day. or more, in the form of sugar and alcohol. Alcohol content has increased in recent years, as modern production involves leaving fruit to ripen longer on the vine, so it becomes more sugary, resulting in more alcoholic 150 ml 250 ml 750 ml wine with more calories. (5 fl oz) (8.5 fl oz) (25 fl oz)

Beer WHY IS BEER SOLD IN TINTED BOTTLES? Probably the first alcoholic drink created by humans, beer is the world’s most widely produced Dark or tinted glass blocks and consumed alcoholic beverage. This is reflected the ultraviolet light that would in the enormous variety of beers now available. otherwise cause the beer to Brewing spoil. This process is known Brewing relies on mobilizing the sugars in grain. This is usually begun as “skunking” or being by malting—letting the grain sprout, so that it converts its stored starch “light struck.” to the sugar, maltose. Brewers add flavors to the ground grain, such as hops (a flower that imparts bitter or zesty tastes), and the brew is then fermented with yeast. The finished beer can be left with some yeast to continue to mature in a cask, or it is stored, yeast-free, in bottles or kegs. 1 Producing the mash 2 Lautering 3 Boiling Milled, malted grain and The initial extraction fluid— The wort is boiled for up to hot water are mixed to produce wort—is drawn off, and then the solid the mash. Enzymes in the grain remains of the malt are sparged, or two hours to deactivate enzymes, and to bring out bitterness. Hops convert its starches into sugar. washed, to release remaining sugars. are added at this stage. 6 Conditioning 5 Fermenting 4 Centrifuging The beer is matured with a Yeast is added to the wort and The wort is cooled in a heat exchanger and then put in a second fermentation to develop the mixture is fermented for four to five centrifuge to remove coagulated flavor and carbonation, and cleared of detritus before packaging. days, during which sugars are converted proteins and spent hops. to alcohol and carbon dioxide. IN 2014, BEER BELLY 9.25 GALLONS (35 LITERS) Although beer contains antioxidants, OF BEER WERE B vitamins, and minerals, it is also PRODUCED FOR high in calories due to sugar and EVERY ADULT alcohol content, and is often ON EARTH consumed with fatty foods, leading to weight gain.

Main beer varieties 172 173DRINKS The two basic Western types of beer are ales, made using yeasts that Beer ferment at the top of the brew, and lagers, fermented at the bottom. Top fermentation is quicker and results in more color, flavor, and fruitiness. Types of beer Light lager Beer has been around so long Light lager is brewed using less malt, but that many different types and by converting more of the sugar from methods have evolved around which it is fermented, to give a beer with the world. Brewers often use about the same alcohol content, fewer the main staple crops available, calories, but less body and flavor. so while European and North Lager American beers are made from Bottom fermented in cold conditions, barley or wheat, many people in originally in casks stored away in cool Africa and Asia brew their beer cellars (“lager” is German for “storing”), from millet, sorghum, or rice. In lager is a clean, crisp tasting beer with some parts of South America and about four to five percent alcohol. Africa, when making beers from Wheat beer corn or cassava root, some beer Often known as white beer, these makers aid the brewing process top-fermented beers use a high with their own saliva enzymes, proportion of wheat compared contributed by chewing the crop. to barley, and tend to be foamier, hazier, tart, and fruity. GETTING A HEAD Ale Top fermented, with a robust, hoppy, A head of foam helps to release fruity character, ales are more colorful a beer’s aroma and flavor. Beer and cloudy than lager. Although they develops foam because it is taste stronger, they generally have carbonated and relatively high in similar alcohol content to lager. proteins, which prevent the air Stout bubbles from popping. Generating Stout is a type of ale, in which unmalted and retaining the foam depends on barley is sometimes used to create more variables such as the acidity and browning and rich flavors. Noted for its alcohol content of the beer, and dark color and for retaining its head, stout even the type of glass used. has three to six percent alcohol. Large Reduced beer head beer head Large immobile bubbles Small mobile bubbles HYDROPHILIC HYDROPHOBIC GLASS GLASS



DIETS

Balanced diet Beans, pulses, and fish are suggested sources of protein We all know that we should eat a healthy, balanced diet, but what exactly does OIL DAIRY that mean? It turns out guidelines GRAINS, differ around the world. CEREALS, TUBERS, Government guidelines AND BEANS Many countries’ governments provide nutritional guidelines to help their people make good food PROTEIN choices. These are based on scientific research but are adapted to create an achievable diet in each country. After all, there would be little point recommending a diet so wildly different from the national average that nobody even tries to stick to it. While most countries recommend a diet based United Kingdom FRUIT AND on whole grains and plenty of fruit Starchy carbohydrates VEGETABLES and vegetables, with limited sugar, and fruit and vegetables salt, and fat, guidelines differ from should make up the bulk Five portions of country to country. Some give more of meals, along with smaller fruit and vegetables precise suggestions than others amounts of proteins and dairy a day are advised for the different sources of protein, foods. The lack of sugary foods and the proportions of dairy foods implies they have no place in a healthy diet. suggested vary dramatically. Sugar and oils are SUGAR OIL suggested when US GUIDELINES ADVISE there is a shortfall in calories LESS THAN 10 TEASPOONS DAIRY OF SUGAR A DAY, NOT THE CURRENT AVERAGE OF 22 GRAINS, CEREALS, TUBERS, AND OTHER BEANS Water intake FRUIT BEANS/ The UK recommends India PULSES Indian guidelines 6–8 drinks per day. suggest a diet rich in MEAT/ Water, tea, coffee, grains, dairy foods, and FISH milk, and sugar-free vegetables. Much of soft drinks all count. the protein comes from VEGETABLES Fruit juice’s high sugar pulses, with a smaller content means only amount coming from Homegrown or one small glass should meat. Variety is important locally sourced be consumed daily. in the Indian diet. vegetables are recommended

176 177DIETS Balanced diet Soy-based foods are recommended GRAINS, OIL WHO ARE CEREALS, DAIRY GUIDELINES FOR? TUBERS LEGUMES/NUTS Other than the very young, FISH/SHRIMP the proportions of foods to be eaten apply to everyone, but MEAT/POULTRY the total number of calories consumed should vary depending on age, gender, and activity level. FRUIT EGGS Guidelines VEGETABLES aim to cut meat consumption by half China GRAPHIC GUIDELINES The focus of the guidelines given to Many countries use a pyramid the Chinese people is on to relate the recommended cereals and vegetables, dairy proportions of the main food foods, and smaller amounts groups. Others, such as South of protein. Recommendations Korea and Japan, incorporate a on avoiding food waste are reminder that physical activity is a also included. necessary complement to eating well. GRAINS, CEREALS, OIL The US- JAPANESE TUBERS, AND DAIRY recommended SPINNING OTHER BEANS diet includes a relatively large TOP FRUIT proportion of dairy foods VEGETABLES PROTEIN United States KOREAN Americans are BICYCLE Legumes, dark-green, red encouraged to focus and orange, and starchy on the variety and AUSTRALIAN PYRAMID nutrient density of their vegetables are encouraged food, and to eat fewer high-calorie foods with low nutritional value. They should limit saturated fats, trans fats, sugar, and salt.

Do we need YES supplements? Many experts argue that Many people take multivitamins or other supplements are beneficial, at least supplements as part of their daily routine, for some people, and even if you aren’t but do we really need them? Health in one of the groups that will benefit, experts disagree. taking them won’t do you any harm. They can be thought of as a “safety Vitamin D net,” ensuring good nutrition. Vitamin D helps our bodies to absorb calcium, and No harm is a key factor in bone health. While we receive a There is no evidence that taking small amount of vitamin D from the food we eat, multivitamin supplements causes harm, most is made in our skin when it is exposed to as long as they don’t provide significantly ultraviolet (UV) radiation in sunlight. However, not more than the recommended intake of everyone can get enough sunlight, and many people each nutrient. at higher latitudes may benefit from supplements. Benefits to specific groups 5–7 minutes 5–7 mins Certain groups have been found 10 mins to benefit from particular vitamin 30 supplements—particularly A, C, and D mins in children, and folic acid in pregnant women. These effects don’t show up in large population studies. Acts as a backup SUMMER WINTER Even healthy diets can lack one nutrient or Vitamin D production another occasionally. Vitamin supplements How much vitamin D the KEY may act as a “safety net,” preventing accidental body makes can vary with age, Sun exposure time deficiency. People who take them do show weight, and skin type (darker necessary for daily fewer nutritional inadequacies, but this may skin requires more sunlight), vitamin D dose. be because they also tend to eat healthily. as well as levels of UV exposure. Boosts a poor or restricted diet The amount of sunlight our skin Tropical Many people have a limited or poor receives is affected by our diet, whether because of beliefs, latitude and the seasons. Temperate illness, access to food, or simply being fussy eaters. In these cases, a IS NATURAL multivitamin can help to ensure ALWAYS GOOD? adequate intake of vital compounds. Can be tailored to specific needs Not all “natural” products Males, females, and people of different ages are safe and beneficial. Many and activity levels have different nutritional herbal supplements, and even needs. Tailored supplements are matched to the requirements of the group to which vitamins, can produce you belong. This may be easier than dietary unpleasant side effects or changes to ensure complete nutrition. interact with prescribed medications.

178 179DIETS Do we need supplements? Multivitamins NO Supplements offering multiple nutrients range from minimal to Many experts aren’t convinced comprehensive. Many contain far more than the recommended that supplements are a good idea dose of some vitamins, while they miss out others. Sometimes for everyone. They point to the lack vitamins aren’t absorbed or processed as effectively when of evidence for their benefit in most they are not taken in combination with the foods in which they naturally occur. people, the possibility of harm from high-dose formulas, and TABLET WITH 24 INGREDIENTS their expense. VVVVVVViiiiiittttttiaaaaaatammmmmmmiiiiiinnnnnninBBBBBBA765132 No benefits in general population Large studies of healthy people have V1Vi1VtVVViatmiiiiamttttaamaianimmmmnieniiirBinnnnaB1lDKC29Es not found consistent evidence that multivitamins are beneficial. Specifically, they have been found to have no effect on cardiovascular disease in the general population, or on memory in older adults. 70 PERCENT OF PATIENTS Harmful WHO USE SUPPLEMENTS Some multivitamins contain huge doses OR OTHER ALTERNATIVE of each vitamin, which may be harmful. THERAPIES DO For example, excess iron, selenium, and NOT TELL THEIR DOCTOR vitamin A can be toxic, so it is good practice to keep all supplements out of sight and reach of children. Overdoses cannot be processed If you take large doses of a vitamin or mineral, even if it is harmless, if the amount is more than the body needs, the body will treat it as waste and excrete it. Water-soluble vitamins cannot be stored for later use. FOLIC ACID Not tightly regulated Many vitamins are regulated as foods or Folic acid, also known as vitamin B9, supplements, not drugs. So while safety must is found in pulses, dark-green leafy be proven, composition and quality can vary vegetables, and citrus fruits. Pregnant women are advised to take lots of dramatically. Also, there is often folic acid, as it helps to reduce the no guarantee you are getting risk of spina bifida (defects in the exactly what’s on the label. spinal cord and vertebral column) in Expensive babies. However, as getting enough folic acid from even the healthiest Multivitamins can be expensive, and in diet may be difficult, supplements many cases the money might be better are recommended for all women in the early stages of pregnancy spent on supplementing the diet with and even those trying to conceive. more fresh fruit and vegetables, which also contain beneficial fiber.

Eating patterns DO NIGHTSHIFTS AFFECT NUTRITION? There is no scientific basis for recommending the three-meals-a-day pattern that is common in so Shift workers are at higher risk much of the world. Scientists are trying to discover of obesity, type 2 diabetes, and whether eating differently could make us healthier. other illnesses. This may be due Breakfast like a king? to reduced sleep leading to higher calorie intake, or time- Breakfast is often described as the most shifted activities directly important meal of the day, but is it? People who affecting the body’s daily rhythm. eat breakfast do tend to have lower BMIs (that is, Large breakfast they have lower body fat—see p.190), and Eating a large breakfast may help you resist snacking before those who skip it tend to have a higher lunch, but it isn’t clear whether this will help you consume risk of obesity, heart disease, and fewer calories overall. other related disorders, possibly because of the extra unhealthy BREAKFAST snacks consumed when hunger hits 8:00 midmorning. But recent studies contradict this and suggest that 6:00 10:00 12:00 breakfast-skippers still eat fewer calories overall and suffer no ill effects. Skipping breakfast also extends the fasting period, which may be beneficial (see pp.200–01). Light breakfast Snack Having a small breakfast, or skipping it While it is easy to eat a completely, extends the overnight fast, lot of unhealthy foods as which may be beneficial. However, it snacks and then gain weight, might also encourage you to make less there is no evidence that healthy food choices when you do eat. healthy, portion-controlled snacks are bad. BREAKFAST SNACK Snacking SPANISH RHYTHMS It is difficult to establish whether eating In Spain and the Spanish-speaking Americas, little and often between meals is better for your health than restricting eating to set people follow a markedly different pattern from mealtimes. What is certain is that snack foods are often high in calories and low three meals a day. The midday meal is the largest, in micronutrients. There are good snack options, however—fruit and nuts but cena (dinner) is eaten so contribute to a better diet. late (sometimes midnight) Raiding the fridge Midnight fridge raids and other snacking habits that people eat extra have grown, as traditional social eating customs have become less common in many countries. small meals, such as merienda, to bridge the gap. Tapas can also be eaten in the TAPAS period before dinner.

180 181DIETS Eating patterns MORE THAN Dine like a pauper? 53 PERCENT OF AMERICANS SKIP An old folk saying tells us to eat a light evening meal. BREAKFAST AT LEAST ONCE A Eating certainly affects the body clock—a set of processes occurring all over the body every 24 hours. WEEK, AND 12 PERCENT Body-clock processes in the liver and fat cells may be ALWAYS SKIP IT disrupted by eating late in the day and may compete with the body’s master rhythm. This may explain why meals at night paired with daytime sleep affect the body’s control of blood pressure and sugar level. LUNCH Large midday meal DINNER Light evening meal There is some evidence that Studies in mice found that their 2:00 consuming more of your 6:00 control of blood sugar varies over calories earlier in the day helps the day. This could mean that light reduce feelings of hunger, meals are better when we are less making weight loss easier. active later in the day. 4:00 8:00 10:00 Light lunch Large evening meal Distracted eating, such as a Dinner times have shifted later as desk lunch, may lead to weight working and living patterns have gain. Not paying attention as changed. It seems this may be you eat means you are likely damaging to health, confusing to overeat, or snack later on. the body’s natural rhythms. LUNCH DINNER Weight-gaining regime 0 A.M. FOOD PRE :00 A.M. BIG ME AL While most of us strive to keep body fat down, sumo competitors rely on a P low center of gravity to win wrestling G bouts, so their daily regime of eating 5:0 and activity is aimed specifically at 8:0 developing a bulky physique. Wrestlers’ days start with training 11 done on an empty stomach, then 1 they sleep at midday after an 0 A.M. TRAININ Sumo rules 2 P.M. LONG NAP enormous meal. Scientists can’t Sumo competitors belong to confirm why, but the sumo regime “stables” where their eating does succeed in causing weight gain. patterns are strictly controlled. They prepare their own hearty, protein-rich stew called chakonabe and eat it with huge quantities of rice. A long nap after lunch aims to encourage the body to store calories as fat.

Western diets One plate each Portions are The term “Western” diet has come to mean served at the the processed-food-dominated diet that is now start of the meal, common across the world, but that originated and it is often in the US and Europe. considered rude not to finish the plate Western customs of food. This can make it difficult to respond to the At most Western meals, each person is served a plate of food, body’s fullness cues as the which they are expected to clear. Meals are based around protein (usually meat), with accompaniments of vegetables and meal progresses. carbohydrates. The main course is often followed by a sweet WATER dessert, and sugary drinks are often consumed. Recently, trends have moved away from shared family meals to snacks and preprepared foods eaten on the go or in front of the television. Western pattern diet The modern Western diet is high in saturated fat, salt, sugar, and omega-6 fats (see p.136), and low in omega-3 and fiber. It has been linked to increased rates of obesity, heart disease, type 2 diabetes, and colon cancer. Some studies also suggest that it might contribute to other cancers, inflammatory diseases such as asthma and allergies, and autoimmune diseases. HIGH WESTERN PATTERN DIET LOW RED MEAT HIGH-FAT FRUIT VEGETABLES DAIRY PROCESSED SALT FISH LEGUMES OILS FOOD SUGARY SWEETENED LOW-FAT WHOLE Protein is main DRINKS FOOD DAIRY GRAINS ingredient The star of the LOW WESTERN PRUDENT DIET HIGH meal is the protein: usually meat or Good versus bad diet sometimes fish. Not every Westerner eats badly. The “prudent” diet includes less red Accompaniments meat, processed foods, sugar, and salt, and focuses on whole grains, are chosen to vegetables, fruit, and oils. Examples include the Mediterranean diet complement (see opposite) and the vegetarian diet of the Seventh Day Adventists, its flavor. which provide wide-ranging health benefits.

182 183DIETS Western diets Vegetables as Mediterranean food pyramid MEAT accompaniments Mediterranean meals are based CHEESE Vegetables are around whole grains, beans, YOGURT often viewed as vegetables, and olive oil. Fish, fruit, WINE a necessary but dairy foods, and wine are consumed boring side dish to moderately, and meat and sugary FISH the protein, and are dishes are considered FRUIT served plainly boiled occasional treats. or steamed. Different types are usually cooked separately. WHOLE GRAINS BEANS AND VEGETABLES OLIVE OIL BREAD SPOON The Mediterranean diet FORK WINE GLASS KNIFE The traditional diet followed by some people in Staple is bread the Mediterranean region, and elsewhere, is or potatoes Cold drink characterized by experts as “Mediterranean” and Bread and The drinks served regarded as one of the world’s healthiest. Studies potatoes are the with a meal are suggest that it lowers the risk of type 2 diabetes, most traditional usually cold—wine, high blood pressure, heart disease, stroke, and carbohydrates, water, carbonated soft Alzheimer’s disease. Olive oil consumption is key although rice and pasta drinks, and juice are all in reducing inflammatory responses, reducing are also common. These common. Sugary drinks blood cholesterol levels, and protecting the brain. form an important part can add a lot of hidden of the meal. calories to the meal. INUIT DIET Traditional diets of the Inuit and other Arctic peoples were rich in fish and sea mammals. However, since there was very little opportunity to enrich the diet with plant foods, it was one of the world’s most restricted diets. Polar populations could survive because eating organ meat and chewing whale skin provided SEAL just enough vitamins. NARWHAL WORLD TYPE 2 DIABETES CASES ARE PREDICTED TO DOUBLE BY 2030

Eastern Vegetable dishes diets Vegetables are served as a dish in their Eastern diets vary hugely, from own right, cooked and the sushi of Japan to the curries seasoned with care and of India. But they share a love of valued as a dish of equal spices and strong flavors, and a status to those featuring reduced focus on meat, compared fish or meat. They do not to most Western cuisines. simply accompany the protein part of the meal. Asian customs CHOPSTICKS Despite their differences, Asian cuisines share clear RICE similarities that make them distinct from Western cooking. DISH One is the focus on vegetables as a main component of a meal, rather than as an accompaniment. Another is the TEA reliance on rice as the staple grain. The flavors and ingredients are often chosen for balance, with pairings between dissimilar flavors—sweet and sour, salty and hot—more common than in Western cooking. UNLIKE IN OTHER CULTURES, SHARED THE CHINESE SERVE SOUP AT VEGETABLE THE END OF A MEAL, AS IT IS THOUGHT TO AID DIGESTION DISH SOUP IS GREEN TEA Hot drink REALLY GOOD FOR ME? or broth Fluids form an At very high doses, important part green tea’s active compound is of the meal, in the antioxidant, anti-inflammatory, form of broth, soup, sauce, or tea. and antimicrobial, and is thought Cold drinks are less common, in to help regulate weight, burn some cases possibly due to an Indian Ayurvedic teaching that fat, and control blood cold drinks slow and dilute sugar levels. digestive juices, although science does not support this.

Rice or noodles 184 185DIETS Meals are usually based around rice Eastern diets or noodles, since rice is easily grown OKINAWAN DIET in most Asian countries. White (or Many residents of the Japanese polished) rice is favored, islands of Okinawa stay slim and despite its lower nutritional healthy to the age of 100 or older. value than brown rice, which Their low-calorie diet, high in fruit has the husk left on. and vegetables (including their staple purple sweet potato) and low in refined grains, saturated fat, salt, and sugar, is thought to be the reason, along with an active, community- based lifestyle. SHARED VEGETABLE DISH PURPLE SWEET MAIN DISH POTATO OR BOWL POT OF TEA Higher risk group SHARED FISH DISH Some Asian ethnicities, including south Asians, are more likely to develop cardiovascular disease than others, even when risk factors, such as smoking and diet, are taken into account. As Western food becomes more popular in the East, and more Asian people move to North America and Europe, obesity and its related problems are on the rise in these high-risk populations. Bowl filled It’s in the genes repeatedly The incidence It is common for of heart disease individuals to take suggests people food from shared from south Asia are plates into their own more susceptible bowl as many times as they like to the dangers of a throughout the meal. In many Western diet. This cultures, it is polite to leave some leads experts to food, indicating that you have suspect something eaten your fill and that in their DNA code affects how they the host has met respond to high-fat, your needs. low-fiber food.

Religious and DO CHRISTIANS ethical diets PERMIT ALL FOODS? Many people, in all parts of the world, make diet No, some follow religious choices based not just on taste and health, but on dietary laws, too. Mormonism their ethical or religious beliefs. Whether we follow a prohibits alcohol and caffeine, doctrine-defined set of laws, or a few self-imposed and during the 40 days of Lent, guidelines, we each express our individual convictions through the types of food and drink we consume. Christians deny themselves luxury food or drink as penance. Religion-based diets Religion Permitted Food and dining practices play an ISLAM Food conforming to Fish with fins and Chicken and other important part in most religions, Muslim laws is called “halal,” scales; shrimp— birds (other than both as expressions of religious meaning “allowed.” Animals according to birds of prey) piety and group identity. While must be killed by a Muslim some authorities religions share some similar using a single motion to the practices, most have their own set JUDAISM throat with a very sharp Fish with fins Chicken and other of laws that dictate what types of knife. Observers do not eat and scales birds (other than food and drink they may, and may or drink in daylight during birds of prey) not, consume. Guidelines for food the month of Ramadan. preparation, including animal BUDDHISM Dairy foods slaughter, are also followed. For “Kosher” foods conform to some religions, particular days of HINDUISM Jewish dietary laws. Kosher Dairy foods the week and times of the year also animals must be killed have special dietary significance. using a single motion to the throat with a very sharp JAINISM knife. During the festival of Passover, Jewish people Jains follow an ancient Indian are forbidden from eating religion with the principle of leavened (yeast-risen) bread. nonviolence at its core. They go out of their way to avoid harming Because of their belief in any living creature and nonviolence, Buddhists are eat a very strict often vegetarian or vegan, lacto-vegetarian although this varies with (egg-free) cultures. Some Buddhist diet. They also monks beg for their food exclude onions, and may eat meat if it is garlic, and root given to them, as long as vegetables that it was not killed for them. are necessarily killed when As Hinduism is aligned harvested. with the concept of nonviolence to all beings, the Hindu diet is mostly vegetarian. However, many Hindus do eat meat and animal products, and regional differences in diet exist.

186 187DIETS Ethical and religious diets Ethical diets Animal welfare Environment Some people avoid People address issues Our ethical beliefs can affect factory-farmed meat concerning land use what foods we choose to eat or eggs, or other meat or and global warming and how we source them. Most animal products that they by avoiding red meat, vegetarians don’t eat meat consider to have been which does the most because they believe killing produced inhumanely. environmental damage. animals for food is unethical. Sustainability Waste Similarly, many people express Avoiding some foods— People that have ethical ethical concerns about issues such as types of fish— concerns about food surrounding food production can slow the depletion of waste include so-called when choosing food. these resources, allowing “freegans” who live stocks to recover. off discarded food. Permitted Forbidden Animals with cloven Permitted animals Animals not Pigs, shellfish, Blood Alcohol hooves that chew slaughtered slaughtered fish without scales the cud (cows, goats, according to according to sheep, deer) halal principles halal principles Animals with cloven Permitted animals Animals not Pigs, shellfish, Blood Wine or grape Meat and dairy hooves that chew slaughtered slaughtered fish without scales products from products eaten the cud (cows, goats, according to according to non-Jewish together sheep, deer) kosher principles kosher principles producers Vegetables, fruit, and Most animals Pungent foods with Alcohol most plant-based foods strong flavors, such as garlic and ginger Vegetables, fruit, and Most animals Eggs Beef (extra Pork (extra most plant-based foods prohibition even prohibition even for meat eaters) for meat eaters)

Vegetarians P ROTEIN Eggs and vegans Dairy Nuts Vegetarian and related diets are usually chosen Seeds because of concerns over animal welfare, the environmental impact of eating meat, Beans and pulses or for their health benefits. Less strict are pescatarians, who eat fish, and Vegetables “flexitarians” who occasionally include meat or fish in their diet. Nutrients Leafy greens It is possible to get all necessary nutrients from a IRON Eggs Seeds Fortified bread wholefood vegetarian diet, but vegans will need to Dairy Nuts and cereals consume some processed and fortified products to get everything their body needs. The only reliable, Pulses natural sources of vitamin B12, for example, are meat and animal products, and there is very little vitamin D in vegan products, other than fortified options. Different varieties Grains Vegetarians don’t eat meat or fish, but many eat Fortified salt animal products such as eggs and dairy. In India, eggs aren’t seen as vegetarian, but dairy foods are Nuts encouraged. Vegans choose not to eat any products Seeds that come from animals, including honey. Beans FOOD TYPES VEGETARIAN VEGETARIAN VEGAN Dairy (WESTERN) (INDIAN) Eggs Dairy IODINE Eggs Honey Vegetables Missing out Grain A few nutrients need special attention Fruit in a vegetarian diet. The forms of iron Nuts and seeds and zinc found in plants are harder Beans and pulses to absorb than those in meat, so more must be consumed, and it is difficult to get enough essential omega-3 fatty acids without eating fish.

188 189DIETS Vegetarians and vegans ZINC ENVIRONMENT Mushrooms Rearing livestock for food produces Almond more greenhouse gas than all forms of transport combined, and uses huge amounts of land and water. Switching to a vegetarian diet can cut a meat eater’s carbon footprint by half. Beans and pulses OMEGA-3 FATS 1lb (450g) of wheat 1lb (450g) of beef Whole grains Kale Walnut 25gal (95L) water 5,000gal (19,000L) water Hemp seed Supplements Health benefits Linseed Rapeseed Vegetarians have a reduced chance of obesity and problems such as heart disease, high blood Fortified foods, such Eggs VITAMIN B12 pressure, type 2 diabetes, and cancer. A healthy as yeast extract Dairy vegetarian diet is lower in saturated fat and higher Supplements in fiber, antioxidants, phytochemicals, and other micronutrients. It also Fortified influences the varieties foods, such of bacteria that inhabit as soy milk your gut. Supplements Vitamins Spinach Minerals Microbes Mushrooms Fiber Antioxidants Sunlight Vegetarian diets are high Fiber feeds the Eggs VITAMIN D in many key vitamins good bacteria and minerals KEY Vegetarian options in your gut, Vegan and vegetarian options 29 PERCENT which help keep Fortified foods and OF INDIANS supplements to a vegan diet ARE VEGETARIAN, your digestive VERSUS 3 PERCENT system healthy OF AMERICANS LARGE INTESTINE

FOOD Metabolism Metabolism refers to our body’s vital chemical processes, including extracting energy from food and using it to build molecules and repair our cells. Around 40–70 percent of the energy we burn each day goes into these basic metabolic functions—the proportion depends on how physically active we are. 2 Build and repair Amino acids circulate through the bloodstream and are used by cells throughout the body to build proteins used for growth and maintenance. Excess converted 3 to glucose Any excess amino acids that have not been used to make INE INTERIOR proteins are converted by the liver into glucose. AMINO INTEST ACIDS PROTEIN AMINO ACIDS AMINO GLUCOSE ACIDS FATTY ACIDS GBLLUOCOODSEVIENSSAEL FOOD SUGARS 1 Food broken down 4 Main energy source The body digests the food and drink Glucose travels in the blood that we consume, breaking it down into basic biochemical components or building blocks: amino acids, fatty and provides body cells with a ready source of energy. Any acids, and sugars. that is not used is stored as glycogen. Energy budget YOUR BODY MASS INDEX (BMI) IS SIMPLY YOUR The way in which our body processes energy may WEIGHT IN KG DIVIDED be understood in terms of an energy budget. How BY THE SQUARE OF YOUR much energy we put in—through our food—and HEIGHT IN METERS how much we expend—our levels of activity— determine what we have left over—our fat stores.

190 191DIETS Energy budget BURNING FAT TO KEEP WARM Brown fat DOES HAVING A used up in SLOW METABOLISM Recently, scientists have discovered that reactions MAKE YOU PUT ON WEIGHT? some adults have stores of brown fat that that create burns to keep us warm. Previously, they heat No difference has been found thought only babies had brown fat. They between the metabolisms of have also discovered beige fat, which Regular overweight and slim people. can change to an energy-burning state white fat If anything, metabolic rate when the environment changes, such stores energy as when the temperature drops. increases as your body Finding ways to maintain this burnable size increases. fat in the long term could lead to treatments for obesity. Losing weight GLUCOSE AND FATTY ACIDS GLYCOGEN TO ENERGY When we deprive it of food, our body TO ENERGY exploits its stores of energy. First, it Fat burning AMINO ACIDS uses all available glucose in the Glucose burning If the body does not have TO ENERGY blood. Glucose is replenished as the If the body has a good enough glucose to burn, it liver breaks down its glycogen store. supply of glucose, it will use will next turn to its fat Protein burning When glycogen runs out, the body this as its primary source of stores for energy. When starved, the body turns to its fat stores. So the only energy until it runs out. will take the extreme way to lose weight is to remain in an measure of using amino energy deficit—using more calories acids for energy. than you take in—for a prolonged period. Do this too strictly for long, however, and muscles waste, as the body breaks them down to liberate amino acids for energy. Putting on weight Glycogen Glycogen store half full store full When we consume more calories than we expend through GLUCOSE GLUCOSE metabolism and exercise, we store TO GLYCOGEN TO STORED FAT the extra energy, first as glycogen, Storing carbohydrates Storing fat then as fat. Fat is stored under the If we have a surplus of glucose that our When the liver reaches its full capacity for skin (subcutaneous) and around our body has not used for energy, this is storing glycogen, any extra calories that are organs in our abdominal cavity taken up by our liver cells and stored as a consumed are converted to fat and placed in (visceral). It is visceral fat that leads complex carbohydrate called glycogen. stores throughout the body. to obesity-related diseases. White fat cells also secrete hormones and hormonelike molecules, which affect food intake (see pp.14–15) and insulin secretion and sensitivity (see pp. 216–17).

Diet and exercise It’s commonly thought that exercise keeps HIGH-CAL ORIE DIET HIGH BMR us slim, but recent research seems to be casting doubt. While exercise is good for Fat/solid Large you in many ways, an extra trip to the body shape amount gym may not actually do that much of fat for your waistline. Large muscles Effects of exercise KEY Exercise can help with weight loss, and particularly weight maintenance, Calories but it doesn’t have as large an effect Exercise as might be expected. In the short term, exercise seems to boost our XERCISE RCISE basal metabolic rate (BMR—the amount of energy HIGH EXE used daily at rest). It may do this by increasing High-calorie diet, high exercise If you exercise a reasonable amount, you are likely muscle mass, since muscle burns more calories at to have strong muscles and a high basal metabolic rate. However, if you also eat a high-calorie diet rest than fat does. However, new studies suggest you can still store fat and become overweight. that once we reach a certain sustained high level of exercise, our body may compensate by actually reducing our basal metabolic rate. High intensity exercise HIGH-CAL ORIE DIET Large amount High-intensity interval training (HIIT) seems to reduce Fat/flabby of fat body fat more than other exercise, but why is not clear. body shape One study found that for the same calories burned, HIIT reduced nine times more subcutaneous fat than regular exercise. Paradoxically, it also increased fitness for both aerobic (sustained, low-intensity) and anaerobic (high-intensity) exercise. SPRINT CYCLE Small muscles Intensity LOW E ENDURANCE CYCLE LOW BMR High-calorie diet, low exercise Time Taking in a lot more calories than you burn leads to Peaks of intensity rapid weight gain and fat accumulation. If you don’t HIIT involves working at full power for short periods—for take much exercise, you are likely to have undeveloped example, cycling all-out for just 10 seconds, then resting muscles and a low basal metabolic rate. before repeating the intense burst.

192 193DIETS Diet and exercise CALORIES BURNED DIETLOW-CALORIE HIGH BMR It takes a lot of exercise 200 10 mins RCISE Muscular to burn off even a few 120 Dancing Small body calories. Walking at a 90 Cycling amount shape moderate pace for 50 Walking 15 minutes, for example, of fat Large muscles will burn off only the 200 calorie equivalent of the calories granola bar in a small apple. Because of this, it can be fairly difficult to create a calorie deficit through increasing levels of exercise alone. HIGH EXE Gentle exercise improves mood ALZMHEOIOMDER’S and seems to protect against STROKE Low-calorie diet, high exercise Alzheimer’s disease Reducing your overall calorie intake while increasing your levels of exercise is the most effective way to People who are moderately active lose weight. It will also help you preserve muscle are less likely to have a stroke and change shape through depletion of fat stores. Regular exercise helps to keep your SCLE muscles strong and toned LUNGS MU Your heart becomes stronger and more efficient with exercise LOW-CALORIEDIET Small Regular exercise can help prevent the HEART ERCISE amount buildup of fat in the liver LIVER Thin of fat body Weight-bearing exercise helps shape build bone density in children; Small in adults, it prevents it from muscles being lost LOW EX Wider health benefits LOW BMR Even if it isn’t as useful for BONES Low-calorie diet, low exercise weight loss as we once thought, Someone who is relatively inactive can maintain a regular exercise offers a huge healthy weight by eating a low-calorie diet. However, number of health benefits. they will be missing out on the many health benefits It can lower your chance of exercise offers. developing type 2 diabetes, stroke, or heart attack, reduce your blood pressure, and improve your cholesterol levels, independent of weight loss.

Calorie counting DOES LOW-FAT MEAN LOW-CALORIE? Counting the calories in the food we eat is a basic strategy of weight management. While a “calorie- Low fat diets do tend to controlled” diet may be a useful way to monitor our reduce calories overall, so intake, we shouldn’t make food choices on calorie can work for weight loss. But content alone. For optimum health, we must still many low-fat products have eat a balanced diet containing all food groups. more sugar and salt added, meaning they aren’t always DENSITY the healthier choice. M DENSITY HIGH MEDIU Energy-dense foods DOUGHNUT PEPPERONI PIZZA Energy-dense foods typically contain 125kcal/ 74kcal/28g (1oz) a high proportion of fat, and often 1oz (28g) lots of sugar. They include baked Medium foods made using butter POTATO CRISPS energy density and oil, and many 157kcal/28g (1oz) These foods have a more processed foods. balanced combination of fats, carbohydrates, and protein. Some fruits and starchy vegetables could also be included here. CHOCOLATE CAKE 175kcal/28g (1oz) Energy density SELF-IMPOSED RESTRAINT The energy density of a food is the amount of energy A custom practiced by the people of Okinawa, Japan, it contains per unit of weight—usually expressed in hara hachi bu roughly translates as “eat until you are 80 calories per gram (kcal/g). Energy-dense foods provide percent full.” The Okinawans are known for having the more calories per gram than those with low energy world’s highest proportion of centenarians, and their density. A food’s energy density is determined by its approach to eating clearly plays a role in this. Hara proportions of fat, carbohydrates, protein, fiber, and hachi bu contrasts with the traditional Western custom water. Fat contains 9kcal/g, carbohydrates and protein of eating until the plate is completely empty. both contain 4kcal/g, and alcohol 7kcal/g. Fiber and water provide no energy—just structure and bulk.

194 195DIETS Calorie counting What is a calorie? FOOD Measuring calories SAMPLE A food’s calories are measured by A food calorie is a unit used to measure the energy WATER burning a freeze-dried sample in in food. Although the calorie is widely used in the oxygen. The calorific value is context of food, scientists now mainly use the joule measured by how much a volume as a unit of energy, and the kilojoule (kJ) for food of water, surrounding the food, quantities. One food calorie (kcal) converts to increases in temperature. 4.184kJ. Depending on location, food labeling uses either one or both of these units. STEAK LOW DENSITY 50kcal/ 28g (1oz) CARROTS BROCCOLI 27kcal/28g (1oz) 10kcal/28g (1oz) LASAGNA Low energy density 46kcal/ Low in fat, but with a high BEETS 28g (1oz) percentage of fiber and water, these 12kcal/ foods include most vegetables and 28g (1oz) legumes, and brown rice. Low energy density foods tend to be TOMATOES more bulky and filling. 5kcal/ 28g (1oz) BROWN RICE 28kcal/ 28 (1oz) VEGETABLE SOUP 17kcal/28g (1oz) Absorbing calories Portion 45% 20% Varied absorption passing 55% Our bodies don’t treat all foods straight 80% Many of the plant cells that equally. Some are harder to digest through RAW PEANUTS make up nuts aren’t broken than others, which means we don’t the body down as they pass through extract all the calories they contain. our gut, meaning their Furthermore, we are not all same, Portion nutrients remain locked up and one person’s digestive system absorbed inside the indigestible cell may extract more calories than walls. However, in nut butter, another’s from the same meal. the processing has started the digestion process for you, PEANUT BUTTER so you extract more calories.

Low-carb diets Fat burning Proponents of “low-carb” diets claim that By reducing the levels of glucose in limiting our consumption of carbohydrates can our bloodstream, we can force our help us to lose weight and avoid the side effects body into using alternative sources of eratically fluctuating blood-sugar levels. of energy. A sustained lack of glucose can lead to ketosis, a state in which How it works the body burns its stores of fat at a very high rate. In low-carb diets, instead of carbohydrates providing the main BRAIN C source of calories and energy, fats and proteins do. It is claimed that by keeping our blood sugar and insulin levels low, we can CELL train our body to burn its stores of fat. Also, since low-carb diets ELL LIVER are high in protein, and protein helps us to feel full for longer, this enables us to eat smaller portions, reduce snacking between meals, and cut down our overall calorie intake. Ketone body What to eat? Egg-based meal BREA being used for with a high energy in a Anyone planning to significantly KFAST brain cell proportion of protein reduce one of the main food groups Ketone body needs a diet strategy that will OMELET SPINACH produced from compensate. While protein-rich foods and fatty acids in natural fats can replace carbohydrates as the liver sources of energy, high-protein diets often lack fiber, which is essential for healthy digestion and maintaining good cholesterol levels. Including generous servings of vegetables such as broccoli, cauliflower, and lettuce in your diet can boost fiber Daily diet By combining protein-rich foods with bulky intake, contribute micronutrients, low-carb vegetables it is relatively easy to eliminate carbohydrate-rich foods such as Fatty acid and add bulk to meals. pasta, bread, rice, and sugary foods from each meal of the day. released into bloodstream FAT 2 State of ketosis LOW-CARB DIETS CAN Unlike other tissues, the brain can’t use fatty acids as an energy source. Stored fatty acid HELP PEOPLE WITH So when blood glucose is Fatty acid being DIABETES IN THE low, the liver converts fatty used for energy acids into ketone bodies— molecules that provide in muscle cell MUSCL SHORT-TERM CONTROL OF energy for brain cells. 1 Releasing fatty acids E CELL BLOOD-SUGAR When blood glucose levels are LEVELS maintained at a healthy level, insulin levels remain low. This allows the release of fatty acids from fat cells into the bloodstream, which are then used for energy in most cells.

196 197DIETS Low-carb diets WHAT IS THE LIMITED FOODS BEET CONSENSUS ON LOW-CARB DIETS? Some low-carb diets are very restrictive, and as SQUASH well as cutting out foods that are obviously rich Although most medical in carbohydrates, such as pasta and bread, they DIN organizations recognize the limit the intake of many other foods, at least at effectiveness of low-carb diets first. These include all fruit and sweet-tasting CHICKEN for weight loss, very few, if vegetables such as peas and corn. Potatoes BREAST and other starchy vegetables including any, recommend them as squash, carrots, parsnips, beets, and lentils BROCCOLI a long-term health are restricted, as are whole grains including strategy. quinoa and oats. However, many of these foods are key sources of fiber, vitamins, and LUN minerals, which are essential in a healthy diet. SNA Dinner lacks high-carb foods such as pasta and potatoes NER CK CH TUNA CHEESE SALAD Low-calorie, NUTS High-protein, CAULIFLOWER low-carb salad high-fat snacks are makes up the eaten instead of bulk of the meal wheat-based snacks High-protein diets Benefits Drawbacks Low-carb diets are, by MODERATE HIGH- • Protein helps you feel full for longer so you • Research is mixed as to whether these diets will help definition, often also high- PROTEIN DIETS may be less likely to snack between meals you lose weight protein diets. Moderate high-protein diets • A high-protein diet during weight loss can • Protein-containing foods, including meats, are often increase protein intake help you lose fat rather than muscle more expensive above the standard recommended amount— • Protein takes more energy to digest, so • Eating too much animal protein may increase your risk around 15 percent of some of the calories will be burned off of developing heart disease and some cancers total calories. They continue to allow other EXTREME HIGH- • Protein keeps you full for longer so • A very restrictive diet is difficult to stick to, especially food groups, including PROTEIN DIETS you are unlikely to become hungry when socializing carbohydrates. More extreme high-protein • Lots of popular foods, including meat, • Cutting out food groups can lead to a lack of diets dramatically restrict cheese, and butter are unrestricted essential vitamins and minerals carbohydrate intake. Some also encourage • Many extreme diets don’t involve the • Lack of fiber can cause constipation high fat intake. need to count calories • Reliance on animal proteins may put you at risk of diseases including heart disease and some cancers • Cholesterol levels may increase • Kidney problems can become worse as the kidneys have to deal with more protein • May be ineffective if calories aren’t restricted

High-fiber diet IS FOOD WITH ADDED FIBER Diets such as the F-Plan Diet became popular AS GOOD AS FOOD in the 1980s after Dr. Denis Burkitt connected NATURALLY HIGH IN FIBER? the benefits of traditional rural African diets with their high fiber intake. The idea went out Producers may add fiber to of fashion as the focus moved to reducing carbs, cereals, bread, yogurt, and other but it is now becoming popular again. products. Although the fiber is Benefits of a high-fiber diet less varied than natural fiber, the beneficial health As a weight-loss plan, high-fiber diets reduce calories while increasing effects are almost fiber. The diet focuses on eating plenty of vegetables and whole grains, the same. so it fits with governmental guidelines on healthy eating and is recommended by many dieticians. No food is off limits, and the foods What to eat eaten can reduce the risk of obesity, diabetes, and other diseases A high-fiber diet should contain lots of fruit related to insulin resistance. However, some people find high-fiber and vegetables (including skins and peels, where foods unappealing, which may make the diet difficult to stick to. If possible), whole grains, nuts, seeds, beans, and water intake isn’t increased, it can cause short-term constipation. pulses. By swapping to items like whole-wheat bread and high-fiber breakfast cereals, you can easily increase your fiber intake. BREA LUN Leave the skin on SNA fruit to maximize APPLE fiber intake CK CH KFAST BRAN FLAKES WHOLE-WHEAT FIG BANANA SANDWICH DRIED APRICOTS PRUNES A banana contains Switch to PISTACHIOS about 1/10oz (2–3g) whole-wheat of fiber bread for sandwiches ONE STUDY FOUND HIGH-FIBER FOODS THAT PEOPLE LOST WEIGHT SIMPLY Well-known high-fiber foods range from 5 percent fiber BY ADDING FIBER by weight (broccoli) to 15 percent (lentils) and also TO THEIR DIETS, include whole-wheat pasta, avocados, and peas. CHANGING Eclipsing all of these, however, are chia seeds, NOTHING which are 37 percent fiber, four-fifths ELSE! of which is soluble. That is why when soaked in water, chia seeds dissolve into a gloopy gel—a useful consistency for desserts. Chia seeds soaked in water form a gel