Current Research
Background Information:
Childhood overweight and obesity are highly prevalent in the United States, affecting at least one-third of children and adolescents. Since 1980, the rates of obesity have more than tripled for children aged 2 to 19 years. The risk of obesity is higher among minority and low-income populations.
Overweight children and adolescents are at greater risk for health problems compared to their normal-weight counterparts and are more likely to become obese adults. Obese children and adolescents are more likely to develop serious illnesses such as type 2 diabetes, hypertension, high cholesterol, stroke, heart disease, cancer, and arthritis. Other reported health consequences of childhood obesity include eating disorders and mental health issues such as depression and low self-esteem.
Many factors contribute to a child developing obesity. These include:
Effects of Interventions:
School-Based Interventions:
There is moderate evidence that school-based obesity interventions are effective in preventing obesity or overweight in children. Two randomized controlled trials evaluated the effects of diet interventions on weight-related outcomes and showed a decrease in body mass index (BMI) over a period of 1 year (1)(2). These specific studies focused on the prevention of weight gain and focused on promoting a healthy diet through the reduction of the consumption of carbonated drinks. Physical activity interventions in schools had an impact on BMI, waist circumference, skinfold thickness, and percentage of body fat in children. These studies were designed to prevent weight gain, reduce sedentary screen-viewing time, and promote participation in physical activity.
There is insufficient evidence to determine if school-based combination diet and physical activity interventions prevent obesity in overweight in children (6). Three research studies assessed the effect of a combined diet and physical activity intervention on weight-related outcomes (2)(3)(4). They were not effective at reducing BMI, prevalence of obesity and overweight, percentage of body fat, waist circumference, and skinfold thickness. These were designed to affect weight gain and included intensive classroom physical activity lessons led by teachers, moderate physical activity sessions, nutrition education materials, and healthy diet promotion.
School Based Interventions with a Home Component:
There is high evidence that physical activity interventions in a school-based setting with an additional home component prevent obesity or overweight in children. A study focused exclusively on physical activity interventions (8). This was a physical activity program that included both an educational and environmental approach to physical activity. Another study focused on the reduction of sedentary behavior associated with television, videotape, and video game use in the home (5). Both studies demonstrated great improvements in BMI, waist circumference, and skinfold thickness due to the interventions.
School Based Interventions with a Community Component:
The strength of evidence is moderate that diet with physical activity impacts body mass index (BMI) in a school-based setting with a community component. This study specifically targeted weight gain prevention (7). The focus of the intervention varied greatly— both education and community structural changes were made to promote diet changes and physical activity. In many of the school based interventions with a community component, sample sizes were small and not able to be generalized.
Combined Intervention: School, Home, and Community
There is strong evidence that combined diet and physical activity interventions in a school-based setting with home and community components prevent obesity or overweight. This study reported on significant changes in BMI. The study also found a significant decline in BMI in followup when compared with baseline measures in favor of the intervention. Overall, studies of a combination of diet and physical activity interventions based in school, home, and community settings generally showed significant improvements in weight outcomes. This interventions focused mostly on education, healthy diets and increased physical activity for obesity prevention (10).
Gaps in Knowledge:
There is little to no evidence to determine whether the following interventions are sufficient to reduce childhood obesity:
Childhood overweight and obesity are highly prevalent in the United States, affecting at least one-third of children and adolescents. Since 1980, the rates of obesity have more than tripled for children aged 2 to 19 years. The risk of obesity is higher among minority and low-income populations.
Overweight children and adolescents are at greater risk for health problems compared to their normal-weight counterparts and are more likely to become obese adults. Obese children and adolescents are more likely to develop serious illnesses such as type 2 diabetes, hypertension, high cholesterol, stroke, heart disease, cancer, and arthritis. Other reported health consequences of childhood obesity include eating disorders and mental health issues such as depression and low self-esteem.
Many factors contribute to a child developing obesity. These include:
- Genetic factors
- Home influences
- The school environment
- Factors in the local community
- Policies and legislation
Effects of Interventions:
School-Based Interventions:
There is moderate evidence that school-based obesity interventions are effective in preventing obesity or overweight in children. Two randomized controlled trials evaluated the effects of diet interventions on weight-related outcomes and showed a decrease in body mass index (BMI) over a period of 1 year (1)(2). These specific studies focused on the prevention of weight gain and focused on promoting a healthy diet through the reduction of the consumption of carbonated drinks. Physical activity interventions in schools had an impact on BMI, waist circumference, skinfold thickness, and percentage of body fat in children. These studies were designed to prevent weight gain, reduce sedentary screen-viewing time, and promote participation in physical activity.
There is insufficient evidence to determine if school-based combination diet and physical activity interventions prevent obesity in overweight in children (6). Three research studies assessed the effect of a combined diet and physical activity intervention on weight-related outcomes (2)(3)(4). They were not effective at reducing BMI, prevalence of obesity and overweight, percentage of body fat, waist circumference, and skinfold thickness. These were designed to affect weight gain and included intensive classroom physical activity lessons led by teachers, moderate physical activity sessions, nutrition education materials, and healthy diet promotion.
School Based Interventions with a Home Component:
There is high evidence that physical activity interventions in a school-based setting with an additional home component prevent obesity or overweight in children. A study focused exclusively on physical activity interventions (8). This was a physical activity program that included both an educational and environmental approach to physical activity. Another study focused on the reduction of sedentary behavior associated with television, videotape, and video game use in the home (5). Both studies demonstrated great improvements in BMI, waist circumference, and skinfold thickness due to the interventions.
School Based Interventions with a Community Component:
The strength of evidence is moderate that diet with physical activity impacts body mass index (BMI) in a school-based setting with a community component. This study specifically targeted weight gain prevention (7). The focus of the intervention varied greatly— both education and community structural changes were made to promote diet changes and physical activity. In many of the school based interventions with a community component, sample sizes were small and not able to be generalized.
Combined Intervention: School, Home, and Community
There is strong evidence that combined diet and physical activity interventions in a school-based setting with home and community components prevent obesity or overweight. This study reported on significant changes in BMI. The study also found a significant decline in BMI in followup when compared with baseline measures in favor of the intervention. Overall, studies of a combination of diet and physical activity interventions based in school, home, and community settings generally showed significant improvements in weight outcomes. This interventions focused mostly on education, healthy diets and increased physical activity for obesity prevention (10).
Gaps in Knowledge:
There is little to no evidence to determine whether the following interventions are sufficient to reduce childhood obesity:
- Interventions tested in the primary care or childcare settings
- ††Environment-based and policy-based interventions (agriculture policies and regulations on food retailing and distribution)
- Consumer health informatics interventions (9)