The nation’s childhood obesity epidemic: Health disparities in the making
We have not always been a nation in the midst of an obesity epidemic. In the 1960s and 1970s only 13 percent of U.S. adults and 5 to 7 percent of U.S. children were obese. Today, 17 percent of our children, 32 percent of adult males, and 36 percent of adult females are obese. Although obesity has increased across all racial and ethnic groups, it affects some groups more than others. Black (50 percent) and Hispanic women (45 percent) have the highest adult obesity rates. Among children, Black adolescent girls (29 percent) and Mexican-American adolescent boys (27 percent) are most affected (Flegal, Carroll, Ogden, & Curtin, 2010; Ogden & Carroll, 2010a, 2010b).
Obesity kills; it is now the second leading cause of death in the U.S.and is likely to become the first (Mokdad, Marks, Stroup, & Gerberding, 2004). Unless this epidemic is successfully addressed, life expectancy will actually decline in the U.S. (Olshansky et al., 2005). Not only do obese individuals die earlier, but their quality of life is severely compromised; they are far more likely to suffer from diabetes and its complications — kidney failure, blindness, leg amputations — as well as stroke, breast and colorectal cancer, osteoarthritis and depression (Jebb, 2004).
Obesity often begins in childhood and is linked to psychological problems, asthma, diabetes and cardiovascular risk factors in childhood. Because many obese children grow up to become obese adults, childhood obesity is strongly linked to mortality and morbidity in adulthood (Reilly et al., 2003). Because obesity disproportionately affects certain racial and ethnic minority groups in both child and adult populations, it underlies many of the health disparities facing our nation.
This rapid increase in obesity is not the product of changing biology or genes; it is the product of an obesogenic environment that promotes inactivity and overeating. How did this happen? As a society, we have changed the types and quantities of food we eat, reduced physical activity, and engaged in more passive leisure-time pursuits.
In 1975, 47 percent of women with children under age 18 worked outside the home; in 2009, 72 percent did so and among women with children 6 to 17 years of age, 78 percent were employed (U.S. Bureau of Labor Statistics, 2010). With more time spent working outside the home, there was less time for home activities including food preparation. It will come as no surprise that the per capita number of fast-food restaurants doubled between 1972 and 1997, and the number of full-service restaurants rose by 35 percent (Chou, Grossman, & Saffer, 2004). In the 1960’s, only 21 percent of a family’s food budget was spent on dining out (Jacobs & Shipp, 1990). In 2008, it was 42 percent (U.S. Bureau of Labor Statistics, 2011). One national survey found that 30 percent of children ages 4 to 19 years of age ate fast food daily (Bowman, Gortmaker, Ebbeling, Pereira, & Ludwig, 2003). Fast food and convenience food is inexpensive but high-calorie and low in nutritional value. Available per capita calories increased from 3,250 calories per day in 1970 to 3800 calories per day in 1997 (Chou et al., 2004). Fast-food restaurants are more common in ethnic-minority neighborhoods (Fleischhacker, Evenson, Rodriguez & Ammerman, 2011) and the fast food industry disproportionately markets to ethnic minority youth (Harris, Schwartz, & Brownell, 2010).
The per capita consumption of high fructose corn syrup — the mainstay of soft drinks and other sweetened beverages — has increased from 38.2 pounds in 1980 to 868 pounds in 1998 (Chou et al., 2004). In 1942, annual U.S. production of soft drinks was 90 8 oz. servings per person; in 2000, it was 600 servings (Jacobson, 2005). Soft drinks and juice drinks make up six percent of all calories consumed for 2 to 5 year olds, 7 percent for 6 to11 year olds, and more than 10 percent for 12 to 19 year olds. While children 2 to 11 years old get more of their calories from milk than soda, the opposite is true for youth 12-19 years old. Female teens get 11 percent of their total calories from sodas or juice drinks but only six percent of their calories from milk (Troiano, Brefel, Carroll, & Bialostosky, 2000).
Sodas and other sweetened beverages are readily available in our nation’s schools. Vending machines are placed in almost all of the nation’s middle and high schools (Weicha, Finkelstein, Troped, Fragala, & Peterson, 2006) and are in approximately 40 percent of our elementary schools (Fernandes, 2008). Both school vending machine and fast food restaurant use have been associated with increased sugar sweetened beverage intake in youth (Weicha et al, 2006). When vending machines are placed in elementary schools, black children are more likely to purchase a soft drink from these machines (39 percent) compared to white children (23 percent) (Fernandes, 2008).
Not only have our dietary habits changed, but our energy expenditure has changed as well. During the second half of the twentieth century, there was a wholesale movement of Americans from the cities to the suburbs; one half of all Americans now live in the suburbs. Low density neighborhoods were attractive, but these homogeneous residential enclaves, with no mixed-use commercial access, meant that a car was required to buy a newspaper or a quart of milk. The U.S. turned into a nation of drivers; only 1 percent of all trips are on bicycles and 9 percent are on foot. Approximately 25 percent of all U.S. trips are less than one mile but 75 percent of these are by car (Frumkin, 2002). It is not surprising that measures of county sprawl have been associated with both minutes walked and obesity (Ewing, Schmid, Killinsworth, Zlot, & Raudenbush, 2003).
Opportunities for physical activity used to be a common component of each child’s school day. Unfortunately, these opportunities are declining especially in our nation’s secondary schools. While 87 percent of schools require physical education in grade eight, this declines to 47 percent in grade 10, and only 20 percent in grade 12. A minority of youth participate in intramural sports or activity clubs (<20 percent) or varsity sports (~35 percent). Further, ethnic minority youth and those from poverty backgrounds are significantly less likely to participate in any type of sport or activity club (Johnson, Delva, & O’Malley, 2007).
In 1969, approximately half of U.S. children walked or biked to school, and 87 percent of those living within one mile of their school did so. Today, less than 15 percent of U.S. school children walk or bike to school (Centers for Disease Control, 2005); among those who live within one mile of their school, only 31 percent walk, and for those living 2 miles or less from the school, only two percent bike to school. A third of U.S. children go to school on a bus and half are taken by private vehicle (Centers for Disease Control, 2002).
Not only are Americans spending more time in their cars driving to work or school or to meet their daily shopping needs, but their leisure time activities have become more sedentary. Television sets are found in almost every U.S. household and many children have TVs in their bedrooms. A recent report by the Kaiser Family Foundation (Rideout, Foehr, & Roberts, 2010) noted the explosion in media content use of all types (TV, music/audio, computer, video games, and cell phones) from more than six hours per day in 1999 to more than seven hours per day in 2009. Most notable were the large discrepancies found between minority and majority youth; Black and hispanic youth average > nine hours of media use per day compared to six hours among white children. Numerous studies have documented the link between sedentary leisure activities and poorer physical and psychological health; further, intervention studies have shown that lowering the amount of time spent in sedentary activities is associated with reductions in children’s body mass index (Tremblay et al., 2011).
A number of critics have argued that U.S. farm subsidies have resulted in mega farms producing so much corn and soybeans that the price of high-fructose corn syrup, hydrogenated fats from soybeans, and corn-based feed for cattle and pigs is kept artificially low. This, in turn results in low prices for fast food, corn-fed pork and beef and soft drinks. In contrast, no such subsidies exist for fresh fruits and vegetables, which are produced in much lower quantities at higher cost to the American public (Fields, 2004). Even the government’s food assistance programs for the poor appear to have an impact on childhood obesity. While the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) and the School Breakfast and National School Lunch Program seem to have a positive impact on obesity in young children, the Supplemental Nutrition Assistance Program (Food Stamps) may have a negative impact, especially in cities where the cost of food is high (Kimbro & Rigby, 2010); the authors suggest that providing subsidized meals may be a more effective way to assure high quality nutrition in poor children. Food stamps, while providing a wider array of food choice, may negatively impact childhood obesity especially when the family lives in an area with high food prices, encouraging purchase of cheaper calorie-dense, less nutritious foods. Other critics have argued that the government’s subsidies for highways have promoted the use of the automobile over public transportation. The U.S. government spends most of its transportation dollars on highways (U.S. Department of Transportation, 2012), and the U.S. has the highest number of vehicles per capita in the world (United Nations, 2007). Further, traffic concerns are one of the primary reasons parents do not allow their children to walk or bike to school (Centers for Disease Control and Prevention, 2002, 2005). Some have argued that the No Child Left Behind policy has resulted in decreased access to recess and physical education in our nation’s schools, as teachers and school districts focus on high stakes testing (Anderson, Butcher, & Schanzenbach, 2010). America’s childhood obesity epidemic is a product of multiple changes in our environment that promote high-calorie, poor quality dietary intake and minimal physical activity. Although our obesogenic environment is affecting all Americans, in many respects, it is disproportionately affecting ethnic minorities and those who live in poorer communities. As psychologists, we are trained to understand the multiple factors that determine human behavior. We understand that there is no single simple explanation for this epidemic nor can we solve it with a single intervention. Instead, psychologists are needed at every level — in our communities and schools, in the health care system, among policy makers, and working with children and their families — if we are to successfully combat this major threat to our nation’s health.
Suzanne Bennett Johnson, PhD, ABPP, is an APA fellow and distinguished research professor at Florida State University (FSU) College of Medicine. She was director of the Center for Pediatric and Family Studies at the University of Florida Health Science Center until 2002, when she became the chair of the Department of Medical Humanities and Social Sciences at FSU College of Medicine, the first new medical school to be established in 25 years. Thanks to continued research funding from the National Institutes of Health (NIH), her work has focused on medical regimen adherence, childhood diabetes, pediatric obesity and the psychological impact of genetic screening on children and families. She has received awards for her research contributions from the Society of Pediatric Psychology, the Association of Medical School Psychologists, and the American Diabetes Association. She is currently president of the American Psychological Association.
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