In the United States, the rate of obesity for all age groups has risen sharply over the past 30 years. Children and adolescents are among those with the greatest increases in obesity rates. During that time period, the percentage of obese children ages 6 to 11 has nearly tripled and for those 12 to 19 years of age the percentage has more than tripled, with both age groups at a 17% obesity rate in 2009. 1
In order to address this serious problem and ultimately begin reversing the upward trend in childhood obesity, we must first understand the many factors contributing to its dramatic increase during the past three decades. Some of the most important of which will be discussed here.
While there are many ways to slice and dice the data, such as by race, economics, geography, etc., there are some factors that have impacted children all across the board.
The food marketplace and how it has changed in the past 30 years is one of the factors contributing to this obesity problem. Fast food is much more prevalent in our culture and more widely available today. These establishments typically offer calorie-dense, low-nutrition meals which are relatively inexpensive compared to healthy alternatives. In addition to being affordable, the portion sizes for these items have increase substantially over the years. Researches Lisa Young and Marion Nestle have documented the increases in portion sizes over the years and have determined that portions from the 1970s through the 1990s for 181 fast-foods and convenience foods have increased more than 60 times. Prior to the 1970s, those same food items had only increased portion sizes 5 times in a 10 year time frame.2 Along with those fast food meals and other meals eaten outside of the home; soda is the drink of choice for many children. Consumption of soda has increased along with portion sizes. The amount of soda being consumed by children who are soda drinkers has increased by 50% since the 1970s.3 When all the food marketplace information is put together, it shows that children are consuming far more calories than they were three decades ago and many of those calories are coming from food sources with low nutritional value.
Another contributing factor is the physical environment and how it is designed. Many children now live in sprawling suburbs which were designed with automobiles being the only mode of transportation considered. Sidewalks and bike trails are almost non-existent with residential streets leading into high-volume, multi-lane thoroughfares which are unsafe for pedestrian traffic. Schools, shopping and other activities are often located well outside of walking distance for most suburban dwellers. Researchers have found that residents of “highly-walkable” neighborhoods had roughly 70 minutes more physical activity than people living in areas that were not conducive to walking. 4
Schools are also partially to blame for the increase in childhood obesity rates. While school lunches must meet the US Department of Agriculture’s nutritional standards, the “competitive foods” they sell a la carte and in vending machines do not. These foods are often high-calorie, low-nutrition snack foods such as crackers, potato chips, candy bars and soft drinks. Sales of these foods, which compete with the regulated school lunches, are often very lucrative for the schools. For example, in 2003-2004, nearly 25% of high schools and middle schools selling competitive foods through a la carte lines generated over $50,000 in revenue from these sales. The extra calories being consumed through these foods are not being expended at school due to a change in the amount of recess/free play time and the decreased focus on physical education classes. As schools struggle to meet government requirements for standardized test scores and regulations such as the No Child Left Behind Act, there has been an increased focus on academics and a reduction in physical activities. For example, since 1989, 40% of elementary schools have reduced or eliminated recess.5
Lastly, parents have a big impact on the weight of their children. Genetics play an important role in determining a child’s predisposition toward obesity. One study estimates that 25-40% of a child’s body mass index can be attributed to heredity.6 However, genetics are only part of the parental equation. Today, many families require both parents be employed just to make ends meet. Families with “stay-at-home-moms” are much less common than they were in the 1970s and that may help explain the increase in fast food and convenience food consumption.7 When both parents work, there is less time for preparation of nutritious foods at home. Children also learn by example and if parents are choosing the wrong foods, children will be more likely to do the same when the situation presents itself to them.
In summary, there are many factors contributing to childhood obesity today with some of the most important discussed here. To change the disturbing upward trend in obesity rates, a multi-faceted approach is necessary. This will require cooperation between schools, parents, government agencies and food producers. Unfortunately, many of these groups have conflicting interests which will likely prevent the necessary changes from happening any time soon.
In the meantime, parents can help by eating fewer meals away from home and preparing nutritious dinners whenever possible. Also, teaching children the importance of eating healthy foods as opposed to junk food may give them a bit of motivation for choosing wisely when faced with food options away from home.
1 Division of Nutrition, Physical Activity and Obesity, National Center for Chronic Disease Prevention and Health Promotion, “Overweight and Obesity: NHANES Surveys” http://www.cdc.gov/obesity/childhood/data.html
2 Lisa R. Young and Marion Nestle, “The Contribution of Expanding Portion Sizes to the U.S. Obesity Epidemic,” American Journal of Public Health 92 (2002): 246–249
3 Simone A. French, Bing-Hwan Lin, and Joanne Guthrie, “National Trends in Soft Drink Consumption
among Children and Adolescents Age 6 to 17 Years: Prevalence, Amounts, and Sources, 1977/1978 to
1994/1998,” Journal of the American Dietetic Association 103 (2003): 1326–1331
4 Brian E. Saelens and others, “Neighborhood-Based Differences in Physical Activity: An Environment
Scale Evaluation,” American Journal of Public Health 93 (2003) http://www.ipenproject.org/documents/publications_docs/Saelens.pdf
5 National Association of Early Childhood Development Specialists in State Departments of Education, “Recess and the Importance of Play, A Position Statement on Young Children and Recess” (2001): 3 http://www.eric.ed.gov/PDFS/ED463047.pdf
6 World Health Organization, “Obesity: Preventing and Managing the Global Epidemic—Report of the
WHO Consultation on Obesity” (Geneva: WHO, 1997)
7 Patricia M. Anderson, Kristin F. Butcher, and Philip B. Levine, “Maternal Employment and Overweight
Children,” Journal of Health Economics 22 (2003): 477–504