Challenging Dogma - Spring 2009

Wednesday, May 6, 2009

Changes are Needed to Improve the Effectiveness of School-Based Obesity Prevention Programs: A Critique Based on Social Ecological Framework – Ashley

Childhood obesity is a serious and chronic condition that affects millions of children in the U.S. The National Health and Nutrition Examination Survey has monitored rates of childhood obesity since the 1970s. During their 1976-1980 survey, 6.5 percent of 6- to 11-year-olds were obese (1). By their 2003-2006 survey, 17 percent of children were obese (2). This represents a 161 percent increase in 30 years. Because childhood obesity puts children at risk for developing many serious conditions including cardiovascular disease, type 2 diabetes, cancer, and kidney disease, it is important that public health interventions focus on reducing the prevalence of the condition (3, 4).
Many short- and long-term studies have examined the impact that obesity interventions have on treating and preventing the condition. The Cochrane Collaboration recently conducted a review of obesity interventions targeted at children. The majority of interventions they reviewed were school-based (19), although one community intervention targeting low-income families, and two family-based interventions were also included. While many of the studies led to changes in student self-efficacy related to physical activity, reduced screen time, and increased fruit and vegetable consumption, few led to actually changes in the weight status of the participants (5). This suggests that our current approach to treating childhood obesity is unsuccessful. We are beginning to move in the right direction by changing policy and modifying environments; however, our current focus on individual health change models, inadequate attention on ethnicity and socioeconomic issues, and failure to create true community level interventions have hindered the success of school-based childhood obesity programs.
Critique 1: Programs Focused on Individual Health Behavior Change Models
Health behavior change models such as the Health Belief Model, the Theory of Reasoned Action, and the Transtheoretical Model focus on individual-level factors to promote behavior change. These models provide individuals with knowledge about the importance of preventing disease, promote positive attitudes toward behavior change, and communicate social norms that endorse the behavior (6). Many current obesity programs use health behavior change models as a major component of their intervention.
A school-based intervention by Muller et al. provided students with eight hours of nutrition education by a trained health teacher. Some of the messages of the course included eat fruits and vegetables every day, reduce consumption of fat, keep active for at least seven hours per week, and reduce television viewing to one hour per day. The hope with this type of intervention is that children will be encouraged to engage in these behaviors (5).
Unfortunately, health behavior change models have not always been successful in promoting behavior change. They assume that individuals think rationally and follow through with their intent to engage in the new behavior (6). When it comes to making food choices, many individuals do not think rationally. They will choose a high fat or high sugar food over a healthy item because it tastes better, is more comforting, or is more convenient to eat. Although a child may indicate that they would be willing to choose an apple over a cookie in the classroom, when presented with a choice of junk food or a healthy item in a real-life situation, the child may choose the unhealthy item.
Using individual health change models to influence eating habits of children is also flawed because they do not make many of their own food choices. Many students receive their breakfast and lunch from school or bring a meal prepared by their caregivers. Children do not generally prepare their own dinners, do not have a say in the type of restaurant their family frequents, and do not control the purchase of items at grocery stores. Therefore, while children may have a greater knowledge of what is healthy through a nutrition education program, they may not have the opportunity to make healthy food choices.
Because children do not have much control over their environment, nutrition and physical activity education programs may be more effective if they make actual environmental and behavior changes, rather than influencing intent to engage in behavior. An elementary school program might focus on taste-testing new fruits and vegetables during class, preparing healthy snacks, hosting a parent-child cooking night, distributing healthy recipes to parents, or organizing a family field day. These activities will teach children about the importance of making healthy nutrition and exercise decisions, will allow them to practice making healthy choices, and will simultaneously help change the child’s environment in a positive manner.
Critique 2: Ethnicity and Socioeconomic Status Have Not Been Addressed
Socioeconomic status is a risk factor for childhood obesity. Children who live in low-income homes are more likely to be obese. Many factors contribute to this association. Low-income children are less likely to participate in extracurricular sports activities due to cost and neighborhoods may be unsafe and discourage outdoor play (3). Both of these factors reduce physical activity. Low-income children may have greater access to high calorie foods and fewer opportunities to access healthy foods due to place of residence (7). Also, schools in poor neighborhoods may be less willing to turn down contracts with vending companies that provide funding to the school.
Race/ethnicity is also a major risk factor for childhood obesity. The overall rate of obesity among 6- to 11-year-olds is 17 percent, but the rate is higher among African Americans, Mexican Americans, and Native Americans. According to NHANES data, 21.3 percent of African Americans who are 6 to 11 are obese and 23.8 percent of Mexican Americans are obese (2). Again many factors contribute to this association. Low Socio-economic status, biological factors, high stress due to discrimination, and differing cultural views on body composition all contribute (7).
A number of changes need to be made in schools to prevent disparities in prevalence of obesity among ethnic minorities and those of low-socioeconomic status. There are over 58 million schoolchildren in the U.S. and almost half of them participate in the subsidized National School Lunch Program; more than seven percent participate in the school breakfast program (7). Many of these children are minorities or come form low-income homes. Children who consume the school lunch receive one-third of the their recommended daily calories from school and children who consume both breakfast and lunch receive three-fifths of their recommended daily calories from school (7). Although the National School Lunch Program is required to meet nutritional standards, many of the meats that are donated or purchased from the USDA contain high-fat contents and fresh fruits are generally only offered in one-half of the meals (7).
Low socioeconomic students may also be differentially impacted by the availability of competitive food items from vending machines, school stores, and school fundraisers. Many states and school districts have enacted legislation that put stricter requirements on competitive foods (8). However, many schools do not follow the policy and schools in poorer neighborhoods are less likely to turn down contracts with vending companies, eliminate school fundraisers involving food, or close down school stores when they provide a source of funding for music, art, and sports activities. Although data has yet to be published, my own research on the Policy, Legislation, and Nutrition project for the state of Washington found that many schools were not complying with policy and many of these schools were in more economically depressed areas.
School-based interventions have not specifically addressed issues of race/ethnicity and socioeconomic status in terms of nutrition and health education. None of the intervention studies reviewed by the Cochrane Collaboration or by Kropski et al. had components that addressed healthy eating using foods from various cultures, or differing body image by ethnicity (5, 9). These are important aspects of nutrition education, particularly in diverse schools, where acculturation may be low.
Critique 3: Multilevel Interventions are Not Being Used
School-based interventions have focused on education and have included some environmental changes. Few to none have truly implemented a hierarchical or multilevel intervention, which may be necessary to reduce the prevalence of obesity among children. The Social Ecological Framework is helpful in understanding how a multilevel intervention works.
The Social Ecological Framework includes five major spheres that influence the behavior of individuals. The innermost layer includes individual characteristics such as knowledge and self-efficacy. The second layer includes interpersonal factors such as family, values, and culture. The third layer (organizational) and fourth layer (community) overlap and include factors such as schools, health care, community organizations, neighborhoods, and faith-based networks. The fifth layer involves public policy and includes government, laws, media, and the food industry (7).
Changes in all five levels of the Social Ecological Framework can be made in schools to help prevent obesity. Public policy can be used to influence what foods are available to children during the school day, ban the use of candy as a reward, and determine how many hours of physical activity children will complete each week. Schools can work with parks and recreation and other community organizations to offer extracurricular sports activities after school. Nutrition and health education can be designed to be culturally sensitive and parents can become involved to change eating habits at home. Obesity prevention programs can be designed to increase knowledge of the importance fruit and vegetable consumption and improve self-efficacy related to physical activity.
Many studies have examined school-based interventions that target multiple layers in the Social Ecological framework, but most are not combined together. For example, a study by VanDongen et al. examined six intervention arms (9). Group 1 received 15 minutes of daily exercise plus six, 30-minute fitness lessons. Group 2 received the fitness component of group one plus 10 hours of nutrition education in school. Group 3 received just the school nutrition component. Group 4 received the school nutrition component plus home nutrition materials for parent and children. Group 5 received just the home nutrition component and Group 6 served as the control and received the usual health curriculum. The study found small decreases in triceps skinfold thickness (TSF) for both boys and girls in the fitness plus school nutrition group; however, greater reductions in TSF measurements might have been observed in a group that received all of the treatment interventions.
Another study by Donnelly et al. examined an intervention that included making changes to food service, providing nine health education sessions by classroom teachers, and 30 to 40 minutes of PE three times a week (9). This study found a six percent increase in physical activity in the intervention group, but did not see changes in student BMI student diet. Lack of change may be due to the nonrandomized design and the small sample size; however, lack of policy changes, inadequate modification to food service, and no home component may also contribute to insignificant results.
In many interventions the interpersonal and public policy levels have been ignored or have not produced effective results. Only recently have public policy changes been made in schools that pertain to nutrition and fitness. As of 2007, only 17 states had implemented policies that set nutritional standards for school meals and snacks that go beyond existing USDA requirements (10). Only 22 states had set nutritional standards for competitive food products that are sold a la carte, in vending machines, school stores, or at bake sales (10). Only 26 states had created policy that limits when and where competitive foods can be sold. In addition, adherence rates in states where policy is implemented varies from school to school (10).
Although the interpersonal layer has been targeted through school-based interventions, they have not proven successful thus far. Many interventions have included home-based components, but they have not resulted in significant changes in BMI, weight, and other research outcomes (9). More research is needed to determine what home-based components will be effective when combined with school-based interventions. In addition, culturally sensitive home-based components should be examined, particularly when interventions are used in diverse schools and neighborhoods.
Childhood obesity is a serious condition that puts children at risk of developing a number of diseases later in life. Rates have risen steadily over the past 30 years and currently over 17 percent of children aged 6 to 11 are obese. School-based programs have been used frequently to address the issue of childhood obesity; however, they have not been very successful in reducing the weight of children. In order to improve the effectiveness of school-based interventions, program developers need to focus more energy on creating multilevel interventions that change policies and school environments and help parents. They should also focus on reducing disparities in the prevalence of obesity among ethnic minorities and children from low-income homes by developing culturally sensitive programs and by addressing environmental factors that differentially impact children from these groups.
Targeting Childhood Obesity through School-Based Programs: An Intervention Designed around the Social Ecological Framework – Ashley Hardesty

In the past, school-based obesity interventions have largely been unsuccessful. They have focused on individual health behavior change models, provided inadequate attention to race and socioeconomic issues, and have failed to implement multilevel components. To help fight childhood obesity and address current flaws in prevention programs, a hierarchical intervention based on the Social Ecological Framework should be implemented in public schools.
A school would begin an intervention by developing a comprehensive wellness policy. As of 2006, public schools have been required by law to create a wellness policy if they participate in the U.S. Department of Agriculture’s School Meal Program (11). The policy is required to cover nutrition education, physical activity, nutrition standards, and other wellness activities (11). A comprehensive wellness policy would go beyond existing USDA guidelines and set rigorous standards for the school breakfast and lunch program and the sale of competitive food items (12). The policy would require daily physical activity for students and the implementation of a tested-effective nutrition and physical activity curriculum. As part of other wellness activities, the school would partner with Parks & Recreation and other community organizations to provide inexpensive after school sports, family field activities, and walk/ride your bike to school days.
As part of the intervention, the school would implement the Eat Well and Keep Moving nutrition and physical activity curriculum. The curriculum includes six components: classroom education, physical education, school-wide promotional campaigns, food service, staff wellness, and parent involvement. Forty-six lessons including Healthy Living and Think about What You Drink are integrated into math, science, language arts, and social studies classes (13). The curriculum includes newsletters and fact sheets for parents in English and Spanish, homework activities for parents and children to complete together, and a parent website (13). The school would build on the parent component by presenting nutrition and physical activity information at parent meetings and by providing healthy recipes that have been adapted from various cultures in parent newsletters.
Beyond Individual Health Behavior Change Models
As stated previously, individual behavior change models focus on imparting knowledge about the importance of preventing disease, promoting positive attitudes toward behavior change, and communicating social norms that endorse the behavior (6). They do not take into account the importance of the environment or the irrationality of human behavior. In addition, they do not take into account the fact that many children do not make their own nutrition and physical activity decisions.
The Eat Well and Keep Moving curriculum does have components of individual behavior change models. It encourages children to eat more fruits and vegetables, reduce their screen time, and limit their consumption of carbonated beverages. These lessons are provided in a classroom setting and are geared toward improving knowledge and attitudes toward behavior change. However, these lessons also work on changing students as a group. For example, the Eat Well and Keep Moving curriculum includes a school-wide two-week memorandum on screen time that encourages students as a whole to make major reductions in their total TV viewing (13).
The Eat Well and Keep Moving curriculum also moves beyond individual behavior change models by promoting environmental changes. The curriculum includes six training modules for food service staff on nutrition education, the Eat Well and Keep Moving curriculum, and the role of food service in promoting healthy eating. The curriculum also includes the Food Service Guide, which provides comprehensive information about making changes to school meals, healthy recipes, preparation tips, and activities for students (13).
Promoting Healthy Lifestyles Across Cultures
Rates of obesity are higher among African Americans, Hispanics, Native Americans, and those living in poverty (1). The high cost of extracurricular sports, unhealthy food environments in low-income schools, and lack of diversity in nutrition and physical activity programs have contributed to higher rates of obesity among these groups (3,7).
The Eat Well and Keep Moving curriculum has been shown to be effective in promoting healthy lifestyle choices among diverse groups of children. The curriculum was tested in a quasiexperimental field trial in primary schools in Baltimore, MD where 91% of the students were African American. The study found that students receiving the curriculum had lower total energy, fat, and saturated fat intakes; an increase in fruit and vegetable consumption; and minor reductions in television viewing (14). This curriculum is able to promote positive behavior change among students of different backgrounds and was likely successful in promoting change in the low-income schools by making environmental changes.
This school-based intervention promotes healthy lifestyle choices among high-risk groups by partnering with Parks and Recreation to provide low-cost after school sports and family field days that encourage physical activity in a safe environment. The intervention also promotes policy changes that help improve the food environments of low-income schools. Many children who take part in the Federal School Lunch and Breakfast programs are low-income children who receive three-fifths of their daily calories from school (7). Reducing the calorie, fat, and saturated fat contents of the school meals and increasing availability of fruits and vegetables will improve the quality of a substantial portion of these children’s’ diet.
Implementing a True Multilevel Intervention
The Social Ecological Framework describes five domains that influence health behavior: individual, interpersonal, organizational, community, and public policy (7). The consensus statement of Shaping America’s Health and Obesity Society states that prevention efforts should fall within the Social Ecological Framework and that children should be viewed in the context of their families, communities, and cultures. By using the Social Ecological Framework the environmental, biological, and behavioral determinants or obesity can be addressed simultaneously (7).
The intervention described earlier contains components in all five domains of the Social Ecological Framework. The Eat Well and Keep Moving classroom lessons increase knowledge of nutrition and physical activity in students and encompass the individual domain. The family component of the Eat Well and Keep Moving curriculum, the family field days, and the inclusion of cultural recipes encompass the interpersonal domain. The involvement of Parks and Recreation and other community organizations to provide inexpensive extracurricular sports and family field days encompass the community and organizational domains. Finally, the comprehensive wellness policy that sets guidelines for the sale of competitive food items, daily physical activity, and the nutrition curriculum encompass the public policy domain.
In the past, school-based obesity programs have been unsuccessful because they focused on individual behavior change models, ignored race and socioeconomic issues, and failed to implement true hierarchical interventions. Using the Social Ecological Framework to create a school-based intervention addresses the flaws of past programs. By producing changes in the environment and working to influence students as a group, the intervention moves beyond individual behavior change models. By addressing environmental issues that disproportionably affect low-income and minority students, and by including a cultural component to parent education, the intervention addresses cultural issues. By making changes to all five domains of the Social Ecological Framework, the intervention becomes truly multilevel or hierarchical. Taken together these changes will help lead to significant reductions in obesity of students.
1. Centers for Disease Control and Prevention. Obesity Prevalence. Atlanta, GA: Centers for Disease Control and Prevention.
2. Ogden CL, Carroll MD, and Flegal KM. High Body Mass Index for Age Among US Children and Adolescents, 2003-2006. Journal of American Medical Association 2008; 299;2401-2405
3. Obesity Action Coalition. Childhood Obesity. Tampa, FL: Obesity Action Coalition
4. Centers for Disease Control and Prevention. Childhood Overweight and Obesity: Atlanta, GA: Centers for Disease Control and Prevention
5. Summerbell CD, Waters E, Edmunds L, Kelly SAM, Brown T, Cambell KJ: Interventions for Preventing Obesity in Children (Review). Cochrane Database System Review 2005; 20(3)
6. Edberg M. Individual Health Behavior Theories (pp. 35-47). In: Essentials of Health Behavior: Social and Behavior Theory in Public Health. Boston, MA: Jones and Bartlett Publishers, 2007.
7. Caprio S, Daniels SR, Drewnowski A, Kaufman FR, Palinkas LA, Rosenbloom AL, et al. Influence of Race, Ethnicity, and Culture on Childhood Obesity: Implications for Prevention and Treatment: A Consensus Statement of Shaping America’s Health and Obesity Society. Diabetes Care 2008; 31:2211-2221
8. United States General Accounting Office Report to Congressional Requesters. School Meal Programs: Competitive Foods are Available in Many Schools; Actions Taken to Restrict Them Differ By State and Locality. Washington, DC: United States General Accounting Office.
9. Kropski JA, Keckley PH, Jensen GL. School-Based Obesity Prevention Programs: An Evidence-Based Review 2008; 16:1009-18
10. Childhood Obesity Action Network. What is Massachusetts Doing about Obesity? Childhood Obesity Action Network.
11. School Nutrition Association. Wellness Policy Boston Public Schools.
Child_Nutrition/Local_School_Wellness_Policies/Boston%20Schol%20District%20-%20Policy%20.pdf Accessed 16 April 2009
12. Centers for Disease Control and Prevention. School Health Index: A Self-Assessment and Planning Guide. Elementary School Version:
13. Harvard School of Public Health. Eat Well and Keep Moving. http://www.eatwelland
14. Gortmaker SL, Cheung LW, Peterson KE, Chomitz G, Cradle JH, Dart H, et al. Impact of a School-Based Interdisciplinary Intervention on Diet and Physical Activity among Urban Primary School Children: Eat Well and Keep Moving. Archives of Pediatric Adolescent Medicine 1999; 153:975-83

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