Expert Commentary

Childhood obesity and policies for prevention: Research roundup

2014 selection of research related to the long-term health consequences of childhood obesity as well as the effectiveness of nutrition and exercise programs to prevent obesity


Over the past 30 years, childhood obesity in the United States has increased alarmingly. According to the Centers for Disease Control and Prevention (CDC), in 1980 just 1 in 14 children ages 6 to 11 was obese, while in 2012 that figure rose to nearly 1 in 5.

To help address this issue, in 2010 First Lady Michelle Obama announced a White House campaign called “Let’s Move,” which aims to “solv[e] the challenge of childhood obesity within a generation.” The campaign incorporates a variety of initiatives aimed at improving children’s diet and exercise, but it was changes to national school nutrition guidelines — put in place by the 2010 Healthy, Hunger-Free Kids Act — that garnered the most attention. Critics argued that they have led to an increase in food waste, though research has indicated a number of positive effects.

In February 2014, a CDC study found what seemed to be signs of progress, including a 43% drop in obesity among children ages 2 to 5 between 2003 and 2012. Subsequent analysis indicated that the study’s findings could have been overstated, however, and June 2014 research, based on the same national survey, found no evidence of a reduction in childhood obesity. Despite the seeming lack of progress, research has found that some school-based programs are effective at preventing obesity and that policies outside of school, such as menu labeling, can help parents to make healthier decisions for their children.

The CDC’s website is a useful resource for statistics on childhood obesity and information about prevention programs. In addition, the following studies offer important insights on these topics:


“Systematic Review and Meta-analysis of the Association between Childhood Overweight and Obesity and Primary School Diet and Physical Activity Policies”
Williams, Andrew J.; et al. International Journal of Behavioral Nutrition and Physical Activity, 2013, Vol. 10, issue 101. doi: 10.1186/1479-5868-10-101.

Abstract: “The objective of this systematic review was to evaluate the effects of policies related to diet and physical activity in schools, either alone, or as part of an intervention program on the weight status of children aged 4 to 11 years. A comprehensive and systematic search of medical, education, exercise science, and social science databases identified 21 studies which met the inclusion criteria…. The policies were clustered into those which sought to affect diet, those which sought to affect physical activity and those which sought to affect both diet and physical activity to undertake random effects meta-analysis. Within the diet cluster, studies of the United States of America National School Lunch and School Breakfast Programs were analyzed separately; however there was significant heterogeneity in the pooled results. The pooled effects of the physical activity, and other diet related policies on BMI-SDS were non-significant. The multifaceted interventions tended to include policy elements related to both diet and physical activity (combined cluster), and although these interventions were too varied to pool their results, significant reductions in weight-related outcomes were demonstrated. The evidence from this review suggests that, when implemented alone, school diet and physical activity related policies appear insufficient to prevent or treat overweight or obesity in children, however, they do appear to have an effect when developed and implemented as part of a more extensive intervention program.”


Government and School Progress to Promote a Healthful Diet to American Children and Adolescents: A Comprehensive Review of the Available Evidence”
Kraak, V.; Story, M.; Wartella, E. American Journal of Preventive Medicine, 2012, Vol. 42, Issue 3. doi: 10.1016/j.amepre.2011.10.025.

Summary: “Schools made moderate progress. Government made limited progress to strengthen the nation’s research capacity to understand how marketing influences diets; and no progress either to create a national ‘healthy eating’ social-marketing campaign, or to designate a responsible agency to monitor and report on progress for all actions. Conclusions: Public-sector stakeholders have missed opportunities to promote healthy eating environments for young people. Government could optimally use all policy tools — incentives and disincentives, education, legislation, regulation, and legal actions. Schools could more effectively engage parents, promote national nutrition standards and available guidelines, provide technical assistance, require mandatory reporting of wellness policies, and evaluate collective efforts.”


Childhood Obesity Prevention Programs: Comparative Effectiveness Review and Meta-Analysis”
Wang, Y.; et al. Agency for Healthcare Research and Quality, Comparative Effectiveness Reviews, No. 115.

Conclusions: “A large number of childhood obesity intervention studies have been conducted in high-income counties over the past three decades. They predominantly took place in school settings, and mostly in the United States. Many of the school-based studies also included intervention components implemented in other settings, such as the home and community. Overall, there is moderate to high strength of evidence that diet and/or physical activity interventions that are implemented in schools help prevent weight gain or reduce the prevalence of overweight and obesity. However, the evidence on the effectiveness of interventions primarily implemented in other settings is largely low or insufficient. We need more research to test interventions conducted in settings other than schools, especially to test the impact of policy and environmental changes. We need to encourage research that tests innovative interventions that take advantage of new technologies, behavioral theories, and methodologies, including systems science.”


“Declining Childhood Obesity Rates: Where Are We Seeing Signs of Progress?”
Robert Wood Johnson Foundation. 2013.

Overview: “In recent years, the national childhood obesity rate has leveled off. Some cities, counties, and states have even reported modest declines in their rates, but progress to reduce racial, ethnic and socioeconomic disparities in obesity rates has been more limited. The places that are reporting declines have taken their own unique approaches to addressing childhood obesity. Many of these places have made broad, sweeping changes to make healthy foods available in schools and communities and integrate physical activity into people’s daily lives. More efforts are needed to implement these types of sweeping changes nationwide and to address the health disparities gap that exists among underserved communities and populations.”


“Prevalence and Trends in Obesity and Severe Obesity among Children in the United States, 1999-2012”
Skinner, A; Skelton, J. JAMA Pediatrics, 2014, Vol. 168, Issue 6. doi: 10.1001/jamapediatrics.2014.21.

Summary: “From 2011 to 2012, 17.3% (95% CI, 15.3-19.3) of children in the United States aged 2 to 19 years were obese. Additionally, 5.9% (95% CI, 4.4-7.4) of children met criteria for class 2 obesity and 2.1% (95% CI, 1.6-2.7) met criteria for class 3 obesity. Although these rates were not significantly different from 2009 to 2010, all classes of obesity have increased over the last 14 years…. Nationally representative data do not show any significant changes in obesity prevalence in the most recently available years, although the prevalence of obesity may be stabilizing. Continuing research is needed to determine which, if any, public health interventions can be credited with this stability. Unfortunately, there is an upward trend of more severe forms of obesity and further investigations into the causes of and solutions to this problem are needed.”


“Long-term Impact of Overweight and Obesity in Childhood and Adolescence on Morbidity and Premature Mortality in Adulthood”
Reilly, J; Kelly, J. 2011. International Journal of Obesity. Vol. 35 Issue 7.

Summary: “Five eligible studies examined associations between overweight and/or obesity, and premature mortality: 4/5 found significantly increased risk of premature mortality with child and adolescent overweight or obesity. All 11 studies with cardiometabolic morbidity as outcomes reported that overweight and obesity were associated with significantly increased risk of later cardiometabolic morbidity (diabetes, hypertension, ischaemic heart disease and stroke) in adult life, with hazard ratios ranging from 1.1 to 5.1. Nine studies examined associations of child or adolescent overweight and obesity with other adult morbidity: studies of cancer morbidity were inconsistent; child and adolescent overweight and obesity were associated with significantly increased risk of later disability pension, asthma, and polycystic ovary syndrome symptoms. Conclusions: A relatively large and fairly consistent body of evidence now demonstrates that overweight and obesity in childhood and adolescence have adverse consequences on premature mortality and physical morbidity in adulthood.”


Keywords: Children, youth, obesity, nutrition, exercise, diabetes, heart disease, research roundup

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