Preventing childhood obesity _ health in the balance_clone

TABLE 1-1 Trends in Food Availability and Dietary Intake of the U.S. Population and of U.S. Children and Youtha 30 Dietary Intake Trend U.S. Population U.S. Children and Youth Portion sizes of foods Portion sizes of most foods consumed by adults Portion sizes for children aged 2 years and older both at home and away from home (except increased for most foods consumed both at home and pizza) increased between 1977 and 1996 away from home between 1977 and 1996 (Nielsen (Nielsen and Popkin, 2003). and Popkin, 2003). Total energy intake derived Total energy intake increased from 18% to 34% Total energy intake increased from 20% to 32% for from away-from-home for adults between 1977-1978 and 1995 children between 1977-1978 and 1994-1996 sources (Lin et al., 1999a). (Lin et al., 1999b). Total energy intake Between 1971 and 2000, average energy intake No significant increased trends in energy intake were increased from 2,450 to 2,618 calories for men observed in children aged 6-11 years between 1977- and 1,542 to 1,877 kcal for women (CDC, 1978 and 1994-1996, 1998 (Enns et al., 2002). 2004a). Total calories consumed by adolescent boys aged Between 1989 and1991 and 1994-1996, total 12 to 19 years increased by 243 between 1977- energy increased 8.6% and 9.5%, according to 1978 and 1994-1996 from 2,523 to 2,766 food supply and CSFII data, respectively calories (Enns et al., 2003). Total calories (Chanmugam et al., 2003). consumed by adolescent girls aged 12 to 19 years increased by 123 between 1977-1978 and 1994-1996 Between 1983 and 2000, calories per capita from 1,787 to 1,910 calories (Enns et al., 2003). increased by 20% (USDA, 2003) (Figure 1-1). Total fat consumption Between 1971 and 2000, the percentage of Between 1965 and 1996, the proportion of energy calories from total fat decreased for men (from from total fat consumed by children decreased from 36.9%to 32.8%) and women (from 36.1% to 39% to 32%, and saturated fat from 15% to 12% 32.8%) (CDC, 2004a). However, the intake of (Cavadini et al., 2000). grams of total fat increased among women and decreased among men (CDC, 2004a) Children aged 6 to 11 years in 1994-1996, 1998 (Figure 1-2). consumed 25% of calories from discretionary fat (USDA, 2000; Enns et al., 2002).

For adolescents aged 12 to 19 years, girls consumed 25% and boys consumed 26% of their calories from added fat (USDA, 2000; Enns et al., 2003). Added dietary sweeteners Between 1977 and 2000, an 83 calorie/day Children aged 6 to 11 years in 1994 to 1996 and 1998 increase in caloric sweeteners was observed consumed 21-23 teaspoons of added sugars in a in the U.S. for all individuals 2 years and older, 1,800-2,000 calorie diet which exceeded the Food representing a 22% increase in the proportion Guide Pyramid recommendation of 6-12 teaspoons of energy derived from caloric sweeteners for a 1,600-2,200 calorie diet (USDA, 1996; Enns et (Popkin and Nielsen, 2003). al., 2002). Between 1982 and 1997, per capita consumption of sweeteners increased 28% (34 pounds) (Putnam and Gerrior, 1999). Dairy and milk consumption Between 1970 and 1997, the consumption of Milk consumption decreased by 37% in adolescent milk per capita decreased from 31 gallons to boys and 30% in adolescent girls between 1977- 24 gallons, while cheese consumption increased 1978 and 1994 (Cavadini et al., 2000). 146% from 11 pounds/person in 1970 to 28 pounds/person in 1997 (French et al., 2001). In 1977-1978, children aged 6 to 11 years consumed four times as much milk as any other beverage, and Americans consumed 2.5 times as much cheese adolescents aged 12 to 19 years drank 1.5 times as and drank 23% less milk per capita in 1997 much milk as any other beverage. In 1994-1996 and than in 1970 (Putnam and Gerrior, 1999). 1998, children aged 6 to 11 consumed 1.5 times as much milk as soft drinks, and by 1994-1996 adolescents consumed twice as much soft drinks as milk (French et al., 2001). continued 31

32 TABLE 1-1 Continued U.S. Population U.S. Children and Youth Dietary Intake Trend In 1997, Americans consumed 24% more fruit Adolescent intake of whole milk decreased while and vegetables per capita than they did in cheese increased. In 1994-1996, for adolescents Fruit and vegetable 1970 (French et al., 2001). aged 12 to 19 years, only 12% of girls and 30% of consumption boys consumed the number of dairy servings Total meat consumption per capita increased recommended by the Food Guide Pyramid (USDA, Meat, poultry, and fish by 19 lbs from 1970 to 2000. In 2000, 2000; Enns et al., 2002, 2003). consumption individual Americans consumed 16 pounds less red meat than in 1970, 32 lbs more poultry, In 1977-1978 children aged 6 to 11 years consumed and 3 lbs more fish and shellfish more total vegetables than children in 1994-1996, (Putnam et al., 2002). 1998 (Enns et al., 2002). In 1994-1996, 1998, only 24% of girls and 23% of boys consumed the number of Food Guide Pyramid recommended fruit servings (USDA, 2000; Enns et al., 2002). In 1994-1996 adolescents aged 12 to 19 years, only 18% of girls and 14% of boys consumed the number of Food Guide Pyramid recommended fruit servings (USDA, 2000; Enns et al., 2003). In 1994-1996 and 1998 the percentages of children aged 6 to 11 years and adolescents aged 12 to 19 years consuming meat, poultry, fish, and eggs were lower than in 1977-1978 (USDA, 2000; Enns et al., 2002, 2003).

Beverage consumption Annual soft drink consumption increased from Soft drink consumption nearly tripled among 34.7 to 44.4 gallons per capita between adolescent boys from 7 to 22 ounces per day 1987-1991 and 1997 (French et al., 2001). between 1977-1978 and 1994 (Guthrie and Morton, 2000; French et al., 2003). Portion sizes of soft drinks increased by 49 calories (from 13.1 to 19.9 fl oz) between 1977 By 14 years of age, 32% of adolescent girls and and 1996 (Nielsen and Popkin, 2003). 52% of adolescent boys consume three or more 8-ounce servings of soda daily (Gleason and Suitor, 2001). Children as young as 7 months old are consuming soda (Fox et al., 2004). NOTE: CSFII = Continuing Survey of Food Intakes by Individuals. aFood availability (per capita intake) is based on food supply data; dietary intake trends are based on measured or self-reported food consumption data. 33

34 PREVENTING CHILDHOOD OBESITY Carbohydrates 600 500 Total Fat 400 Protein 300 Grams per capita per day 200 1970 100 1972 1974 0 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 FIGURE 1-1 U.S. macronutrient food supply trends for carbohydrates, protein, and total fat, 1970-2000. SOURCES: Putnam et al., 2002; USDA, 2003. Percentage of calories 60 Carbohydrates 50 40 Total Fat 30 Protein 20 10 1976-1980 1988-1994 1999-2000 0 1971-1974 Survey years FIGURE 1-2 Percentage of calories from macronutrient intake for carbohydrates, protein, and total fat among adult men and women, 1970-2000. SOURCE: CDC, 2004a.

INTRODUCTION 35 Calories per person per day 2900 Available Calories 2700 Energy Intake (Men) 2500 1974 1978 1982 1986 2300 Energy Intake (Women) 2100 1990 1994 1998 1900 1700 1500 1970 FIGURE 1-3 Available calories from the U.S. food supply, adjusted for losses,a and average energy intake for adult men and women,b 1970-2000. SOURCES: Putnam et al., 2002; CDC, 2004a. aBased on USDA food supply data, calories from the U.S. food supply adjusted for spoilage, cooking losses, plate waste, and other losses increased by 20 percent between 1983 and 2000 (Putnam et al., 2002; USDA, 2003). bDietary intake trends and percentage of calories from macronutrient intake are based on a CDC analysis of four NHANES, by survey year, for adult men and women aged 20 to 74 years from 1971 to 2000 for energy intake (kilocalories), protein, carbohydrates, total fat, and saturated fat (CDC, 2004a). BRFSS data, although it is unclear why this occurred (CDC, 2004b). In 2001, BRFSS respondents were asked to report the overall frequency and duration of time spent in household, transportation, and leisure-time activ- ity of both moderate and vigorous intensity (CDC, 2003c). Although 45.4 percent of adults reported having engaged in physical activities consistent with the recommendation of a minimum of 30 minutes of moderate inten- sity activity on most days of the week in 2001, more than one-half of U.S. adults (54.6 percent) were not sufficiently active to meet these recommen- dations (CDC, 2003c). The physical activity trend data for children and youth are even more limited than for adults. Most available information is on the physical activ- ity levels of high school youth, with limited data available on levels in younger children. Based on the Youth Risk Behavior Survey (YRBS), daily enrollment in physical education classes declined among high school stu- dents from 42 percent in 1991 to 25 percent in 1995 (DHHS, 1996) and increased slightly to 28.4 percent in 2003 (CDC, 2004c). Cross-sectional data collected through the YRBS for 15,214 high school students indicated that one-third (33.4 percent) of 9th to 12th graders nationwide are not engaging in recommended levels of moderate or vigorous physical activity

36 PREVENTING CHILDHOOD OBESITY TABLE 1-2 Trends in Leisure Time and Physical Activity of U.S. Adults, Children, and Youth Trend Adults Children and Youth Available leisure Adults’ free time increased by From 1981 to 1997, children time 14% between 1965 and 1985 aged 3 to 12 years experienced to an average of nearly 40 a decline in their free time by hours per week based on seven hours per week (Sturm, Americans’ Use of Time Study 2005a). (Robinson and Godbey, 1999). Leisure-time There have been increases in An estimated 61.5% of children physical activity reported leisure-time physical aged 9 to 13 years do not activity among U.S. adults participate in any organized based on NHES, NHANES, physical activity during their BRFSS, and trend data on nonschool hours and 22.6% sports and recreational do not engage in any free- participation (Pratt et al., time physical activity based 1999; French et al., 2001). on the 2002 YMCLS (CDC, 2003a). There was a slight increase in self-reported physical activity From 1981 to 1997, children levels among adults, based aged 3 to 12 years experienced on the 1990-1998 BRFSS, an increase in time spent in from 24.3% in 1990 to organized sports and outdoor 25.4% in 1998 (CDC, 2001). activities (Sturm, 2005a). There was a slight decrease in adults reporting no physical activity at all (from 30.7% in 1990 to 28.7% in 1998) (CDC, 2001). Moderate to Based on the 2001 BRFSS, High school students in grades vigorous physical 45.4% of adults reported 9 to 12 are not engaging in activity having engaged in physical recommended levels of activities consistent with the moderate or vigorous physical recommendation of a activity based on the YRBS minimum of 30 minutes of (CDC, 2003b, 2004c; see moderate-intensity activity Chapter 7). on most days of the week in 2001. However, 54.6% of U.S. adults were not sufficiently active to meet these recommendations (CDC, 2003c).

INTRODUCTION 37 TABLE 1-2 Continued Trend Adults Children and Youth Physical education Not applicable Daily enrollment in physical classes education classes declined among high school students from 42% in 1991 to 25% in 1995 (DHHS, 1996) and 28.4% in 2003 (CDC, 2004c). Travel to and Not applicable From 1977 to 2001, there was from school a marked decline in children’s walking to school as a percentage of total school trips made by children aged 5 to 15 years from 20.2% to 12.5% (Sturm, 2005b). An estimated 25% of children aged 5 to 15 years who lived within a mile of school walked or bicycled at least once during the previous month based on the 1999 HealthStyles Survey (CDC, 2002). NOTE: BRFSS = Behavioral Risk Factor Surveillance System. NHES = National Health Examination Survey. NHANES = National Health and Nutrition Examination Surveys. YMCLS = Youth Media Campaign Longitudinal Survey. YRBS = Youth Risk Behavior Survey. and an estimated 10 percent report that they are inactive (CDC, 2003b, 2004c; see Chapter 7). In 2002, the CDC collected baseline data through the Youth Media Campaign Longitudinal Survey (YMCLS), a nationally representative sur- vey of children aged 9 to 13 years and their parents, which revealed that 61.5 percent of youth in this age group do not participate in any organized physical activity during their nonschool hours and 22.6 percent do not engage in any free-time physical activity (CDC, 2003a). Shifts in transportation patterns can affect energy balance. Many tech- nological innovations have occurred over the past several decades such as the increased availability of labor-saving devices in the home, a decline in physically active occupations, and the dominance of automobiles for com- muting to work and personal travel (Cutler et al., 2003). National data tracking trends on the physical activity levels and leisure or discretionary

38 PREVENTING CHILDHOOD OBESITY time of younger children and pre-adolescents are limited. However, an analysis of the available data for children aged 3 to 12 years from 1981 to 1997 (Hofferth and Sandberg, 2001) suggests a decline in their free time by six hours per week—attributed to an increase in time away from home in structured settings—and an increase in time spent in organized sports and outdoor activities over this time frame (Sturm, 2005a). However, it is not possible to determine the overall impact of these changes on children’s physical activity levels. One factor that has influenced overall transportation patterns in the United States is the change in the built environment. Through a number of mediating factors, the built environment can either promote or hinder physi- cal activity, although the role and influence of the built environment on physical activity levels is a relatively new area of investigation. The ways in which land is developed and neighborhoods are designed may contribute to the level of physical activity residents achieve as a natural part of their daily lives (Frank, 2000). There have been many changes in the built environment over the past century or more. For a variety of reasons, Americans moved away from central cities to lower density suburbs, many of the most recent of which necessitate driving for transportation. In these areas, streets were often built without sidewalks, residential areas were segregated from other land uses, and shopping areas were de- signed for access by car. These characteristics discourage walking and bik- ing as a means of transportation, historically an important source of physi- cal activity. Indeed, the amount of time that adults spend walking and biking for transportation has declined in the past two decades, largely because people are driving more (Sturm, 2004). In addition, the more time that Americans spend traveling, the less time they have available for other forms of physical activity. In 2000, Americans spent nearly 26 minutes commuting to their jobs, an increase from 22 minutes in 1990, and the average commuting time was 30 minutes or more in 25 of the 245 cities with at least 100,000 population (Population Reference Bureau, 2004a). Children’s motorized vehicle travel to and from school has increased, though this represents a small proportion of their overall travel. The 2001 National Household Travel Survey (NHTS) indicated that less than 15 percent of children aged 5 to 15 years walked to or from school and 1 percent bicycled (Bureau of Transportation Statistics, 2003). Even children living relatively close to school do not walk to this destination. The 1999 HealthStyles Survey found that among participating households, 25 percent of children aged 5 to 15 years who lived within a mile of school either walked or bicycled at least once during the previous month (CDC, 2002). From 1977 to 2001, there was a marked decline in children’s walking

INTRODUCTION 39 to school as a percentage of total school trips made by 5- to 15-year-olds from 20.2 percent to 12.5 percent (Sturm, 2005b). Based on data collected through the National Personal Transportation Surveys for 1977 and 1990, and the NHTS for 2001, there is little evidence of changes in walking trip length although distance traveled by bicycle has decreased (Sturm, 2005b). Although reduced physical activity has been identified as an unintended consequence of dependence on motorized travel, it is unclear how changes in children’s transportation patterns have reduced their overall physical activity levels (Sturm, 2005b). Media The presence of electronic media in children’s lives, and their time spent with such media, has grown considerably and has increased the time spent in sedentary pursuits, often with reduced outside play time. In 1999, the average American child lived in a home with three televisions, three radios, three tape players, two video cassette recorders (VCRs), one video game player, two compact disc players, and one computer (Roberts et al., 1999) (Figure 1-4). In 2003, nearly all children (99 percent) aged zero to six years lived in a home with a television set and the average number of VCRs or digital video discs (DVDs) in these young children’s homes was 2.3 (Rideout et al., 2003). Television dominates the type of specific media used by chil- dren and youth and is the only form of electronic media for which trend data are available. In 1950, approximately 10 percent of U.S. households had a television (Putnam, 1995) in comparison with 98 percent in 1999 (Nielsen Media Research, 2000). The percent of American homes with more than one television set rose from 35 percent in 1970 (Lyle and Hoffman, 1972) to 88 percent in 1999 (Roberts et al., 1999). Moreover, there has been a ten-fold increase over the same period in the percent of American homes with three or more television sets (Rideout et al., 2003). In 2003, one-half (50 percent) of children aged zero to six years had three or more televisions, one-third (36 percent) had a television in their bedrooms, and nine out of ten children in this age range had watched television or DVDs (Rideout et al., 2003). During a typical day, 36 percent of children watch television for one hour or less, 31 percent of children watch television for one to three hours, 16 percent watch television for three to five hours, and 17 percent watch television for more than 5 hours (Roberts et al., 1999) (Figure 1-5). Two separate national data sources have tracked children’s and adoles- cents’ discretionary time spent watching television. Results indicate that the extent of television viewing differs by age, but also suggest an observed decline in television watching by children under 12 years by approximately four hours per week between 1981 and 1997 (Hofferth and Sandberg,

40 PREVENTING CHILDHOOD OBESITY 7 hours 6:43 6 hours 5 hours 5:29 5:37 6:03 5:19 5:08 4 hours 3:34 3 hours 2 hours 1 hours Girls Boys White Minority All Children 2–7 8–18 year olds year olds FIGURE 1-4 Daily media use among children by age. Media use includes televi- sion, video games, radios, cassette tape players, VCRs, compact disc players, and computers. SOURCE: Rideout et al., 1999. This information was reprinted with permission from the Henry J. Kaiser Family Foundation. 2001). Based on the Monitoring the Future Survey from 1990 to 2001, there was a steady decrease in heavy television watching (three hours or more) among adolescents yet an observed increase in television viewing for one hour or less (Child Trends, 2002). Although children are using other types of electronic media including video games and computers (Roberts et al., 1999; Rideout et al., 2003), television viewing represents a significant amount of discretionary time among children and youth, which is a seden- tary and modifiable activity (see Chapter 8). Consumer Attitudes and Public Awareness Trends in media coverage suggest a striking increase in public interest in obesity. The International Food Information Council (IFIC) has been following U.S. and international media coverage of the obesity issue since