Challenging Dogma


...Using social sciences to improve the practice of public health

Monday, April 30, 2007

New Look, Same Problem: A Critique Of The Food Guide Pyramid’s Continued Reliance On The Health Belief Model For Obesity Prevention – Alison Little

Obesity is perhaps the most widely discussed public health problem in the United States today. Americans receive information about the benefits of good nutrition and the health risks of obesity from several sources. Physicians and other healthcare providers counsel individual patients about these topics. At the population level, people receive information from the media and the government’s obesity prevention initiatives, including the Food Guide Pyramid (1). The Food Guide Pyramid is an educational tool designed by the United States Department of Agriculture (USDA) to promote healthy food choices. The Pyramid was recently redesigned as part of an attempt to address America’s growing obesity problem (2). However, most of the revisions focused on the Pyramid’s nutritional recommendations. The new Food Guide Pyramid still fails to take into account social and behavioral factors that influence eating behaviors, and for this reason it is destined to fail as an obesity prevention tool.

Definition, Prevalence and Consequences of Obesity and Overweight

CDC defines obesity and overweight using body mass index (BMI), which is a measure of weight for height. Adults with BMIs over 25 are considered overweight, and those with BMIs greater than 30 are considered obese (3). A child is classified as overweight if her BMI exceeds the 95th percentile for her age. A child whose BMI is between the 85th and 95th percentile for age is considered at risk of becoming overweight. CDC does not define obesity in children under 18 (4).

In 2004, nearly one third of US adults were obese, and another third were overweight. In addition, approximately half of all children in the US were overweight or at risk. The prevalence of obesity and overweight has been increasing in the United States among all demographic groups for more than two decades. However, the problem is not distributed uniformly throughout the population. Black Non-Hispanics and Mexican Americans are more likely to be overweight or obese than White Non-Hispanics (5). The prevalence also increases as income and educational levels decrease (6).

The consequences of obesity are numerous and far-reaching. These consequences affect obese individuals as well as society at large. Obese individuals are at increased risk of developing serious medical conditions such as type II diabetes and heart disease. These individuals may also struggle socially, as they are often perceived as less intelligent and hardworking than their peers. Obesity’s economic costs for society are substantial. Such costs include publicly-financed medical care for the obese as well as decreased workforce productivity due to obesity-associated morbidities. The costs of decreased productivity alone total more than $20 billion per year in the US (7).

The Role of the Food Guide Pyramid in Obesity Prevention

The US government’s obesity prevention methods center on the Health Belief Model. The Health Belief Model states that when confronted with a health decision, individuals rationally evaluate their own likelihood of being affected by a disease as well as the benefits of and barriers to behavior change. They then develop the intention to change and accordingly change their behaviors (8). The role of the Food Guide Pyramid is to eliminate barriers and facilitate behavior change by providing the public with accurate information about healthy diets.

Originally developed in the early 1990s, the Food Guide Pyramid was revised in 2005 to provide more accurate nutrition information to the public (2). The content of the Pyramid was improved in several ways. For example, the new Pyramid differentiates between refined and whole grains and low and high fat dairy products. It also provides somewhat individualized recommendations and emphasizes the role of exercise in a healthy lifestyle (1).

While its content has improved substantially, the Pyramid itself remains committed to the Health Belief Model as a means of changing eating behavior. It assumes that all individuals have the desire and capacity to develop healthy eating habits. Once provided with the necessary nutrition knowledge, they will successfully adopt healthier diets, leading to weight loss or maintenance. Unfortunately, research suggests that this view is far too simplistic to support long-term dietary improvements and reverse the current obesity trends. The remainder of this critique will examine the ways in which the assumptions underlying the Food Guide Pyramid are flawed.

The Influence of Social, Emotional and Cultural Factors on Eating Behavior

Q: “And how often do you eat beans?”

A: “Oh, everyday. Haitian people eat beans everyday, honey.”

The success of the Food Guide Pyramid as a behavior modification tool rests on the assumption that eating behavior is entirely rational. Research suggests that this is not necessarily the case (9). Food choices can be determined by social, emotional and cultural factors as well as by subconsciously developed habits. For example, individuals may prefer and choose certain foods to which they were exposed as children. They may also prepare foods that their family members will eat and enjoy, even if these are not the healthiest options. These behaviors can become so ingrained in people’s everyday lives that they cease to become conscious choices. People may also use unhealthy foods as rewards for good behavior. After maintaining a healthy diet for a period of time, individuals may feel that they deserve a favorite unhealthy snack. Exceptions may also be made at restaurants or during holidays (9).

Cultural factors can also mediate food choices. The statement that “Haitian people eat beans every day” is an excellent example of an individual’s identification of a specific eating behavior with her culture. While the cultural norm of bean consumption is a healthy one, this is not always the case. For some Asian individuals, white rice is an integral part of a meal. Brown rice, which is more nutritious, may not be perceived as an acceptable substitute (10). Simply informing these individuals that brown rice is a better choice is not enough to change their eating behavior, because the food is a part of their cultural identity.

The above discussion showcases the fact that although people often have the capacity to make rational food choices, they may not always do so. However, even individuals with the best intentions may be unable to execute a rational eating decision due to environmental circumstances. A Detroit study demonstrates that large grocery facilities are less likely to locate in neighborhoods populated with minority and low-income residents. This is important because larger chain stores are more likely than small convenience stores to stock a wide variety of healthy foods, such as fruits and vegetables, at affordable prices (11). A similar study in Eastern Los Angeles found that urban residents had greater access to fast food restaurants than grocery stores. Compounding the problem was the fact that less than one in five grocery stores had a large selection of fresh produce. Nearly half of the grocery stores sold no fruit at all (12). These findings suggest that, especially in low-income, urban areas, residents may not have easy access to the healthy foods they know they should eat. They may knowingly make less healthy choices simply because they are more accessible.

The Importance of Self-Efficacy and Stages of Change in Eating Behavior

Q: “Strive for Five…what does that mean, five per week?”

A: “It’s actually five per day.”

Q: “I need to eat five per DAY?”

Another assumption implicit in the Food Guide Pyramid is that all individuals are ready and able to comply with its recommendations. It ignores important behavioral models such as Social Cognitive Theory and the Transtheoretical Model. Social Cognitive Theory emphasizes that an individual’s perception of her ability to successfully adopt a behavior, or self-efficacy, is an important determinant of behavior change (13). The Transtheoretical Model posits that individuals pass through distinct stages as they strive to reach a behavioral goal, and that individuals in each stage will respond differently to intervention (14).

Factors such as self-efficacy and readiness to change are important because the recommendations put forth by the Food Guide Pyramid are complex and extensive. For a moderately active female in her early twenties, the recommendations include eating 3 cups of vegetables and 7 ounces of grains per day (1). These recommendations are problematic on two levels. First, they use complicated and varied units of measurement. It can be difficult to conceptualize “ounces” of grains and “cups” of vegetables. The daily recommendation of “six teaspoons” of oils is complicated by the fact that lipids are often incorporated into processed foods, which makes it difficult to measure them in terms of teaspoons. These measurement issues may be overwhelming to an individual who is not familiar with nutrition. According to Social Cognitive Theory, if people feel that these recommendations are too complicated for everyday use, they may not be compelled to make any effort to change their behavior (13).

A second problem with the recommendations is the sheer amount of each food that is required. These requirements might seem very high, depending on the individual’s initial level of consumption. For a person who currently eats fresh produce infrequently, the prospect of consuming five fruits and vegetables per day may be daunting. Recommendations that delineate the types of vegetables to be eaten each week present yet another challenge. Some people may feel that trying to comply with these recommendations will only result in failure, and may not attempt any change in consumption at all (13).

An individual’s response to the recommendations of the Food Guide Pyramid may also depend on her readiness to change, as predicted by the Transtheoretical Model (14). A limitation of the Pyramid is that it is only useful to a very specific group of individuals: those who recognize their problems, plan to change their behaviors, and need the nutritional knowledge to support this decision. The Pyramid is not helpful to individuals who have not accepted nutrition as an important issue in their lives. These people must feel that behavior change is necessary and feasible before specific nutritional recommendations become relevant. Similarly, the Pyramid does not benefit individuals who have already tried and failed to adopt healthy eating behaviors. These individuals are likely to be aware of the foods they should eat but are not confident in their ability to adopt these changes. The Food Guide Pyramid fails both of these groups of individuals by neglecting provide them with the advice they need to change their behaviors.

Competing Values in the Determination of Eating Behavior

“I usually buy whatever’s cheapest, unless it’s all the same price. Then I don’t know what to do.”

The Food Guide Pyramid assumes that all eating behavior is motivated by a desire to achieve optimum health. However, research suggests that the motivations underlying food choice vary and are embedded in a life course behavioral model (9). Life experiences and sociocultural factors lead individuals to develop values and preferences about food and eating. An individual’s current life situation, which includes financial resources, cooking ability, nutritional knowledge and family structure, is also important. An individual brings experiences from her past and current life situation to each food decision. At each decision, a variety of factors may be in opposition, including health benefits of a particular food as well as cost, convenience and individual preference. Individuals reconcile these conflicts based on their past and current experience, and health may not always be a top priority (9). Some individuals place a higher value on cost: they buy the cheapest foods either out of necessity or because they were taught as children to value cost highly. Other individuals value convenience or taste over health.

Cost considerations become highly relevant when considering the socioeconomic disparities in obesity. According to Maslow’s Hierarchy of Needs, individuals must satisfy certain basic needs, such as adequate food and water, before they can consider more complex problems such as health (15). For low-income individuals, procuring enough food for themselves and their families can be challenging (6). They are likely to be more concerned with satiating hunger now than preventing disease in the future. Therefore, cost is likely to supersede health as the determining factor of food choice. Unfortunately, this often leads to poor food choices, as foods of low nutritional value are usually less expensive than healthier options like fresh fruits and vegetables (6). In this way, it may simply not be possible economically for these individuals to meet the recommendations of the Food Guide Pyramid.

Conclusion

The Food Guide Pyramid was redesigned by intelligent professionals who undoubtedly care deeply about the health of Americans. The revisions have improved the quality of nutrition information available to the public by increasing the compliance of the Pyramid’s recommendations with the Dietary Guidelines. However, an improved understanding of nutrition by itself is insufficient to change eating behavior. People often eat for reasons other than to satiate hunger and improve their health, and some may value other factors such as cost and convenience more than health. Others may not feel ready or able to adopt changes in their eating behavior. Still others are limited by the availability of healthy foods in their neighborhoods. Until these considerations are acknowledged, it is unlikely that the Food Guide Pyramid will greatly affect America’s obesity problem.

The social and behavioral science theories discussed above are helpful in identifying useful changes to the Food Guide Pyramid. The Food Guide Pyramid could be improved by helping individuals who value cost or convenience identify healthy options that are feasible for their lifestyles. It could also address readiness to change by providing tailored advice for individuals who are in the beginning stages of dietary change, those who are ready to adopt changes and those who are trying to maintain healthy behavior. To its credit, the new Pyramid does offer specific suggestions and encourage incremental dietary changes (1), which may improve people’s self-efficacy. It should also acknowledge that permanent changes in eating behavior require continuous effort and relapses are not uncommon. Accepting relapses as a natural part of the process of weight reduction and maintenance could help people feel less intimidated by the hard work involved in weight loss. They may feel more comfortable making efforts to change and ultimately be more successful in achieving a healthy weight.

References

  1. United States Department of Agriculture.MyPyramid: Steps to a Healthier You.Washington, D.C.: USDA.http://www.mypyramid.gov
  2. Wikipedia.Food Guide Pyramid.Wikimedia Foundation.http://en.wikipedia.org/wiki/Food_guide_pyramid
  3. Centers for Disease Control and Prevention.Overweight and Obesity: Defining Overweight and Obesity. Atlanta: CDC.http://www.cdc.gov/nccdphp/dnpa/obesity/defining.htm
  4. Centers for Disease Control and Prevention.About BMI for Children and Teens.Atlanta: CDC.http://www.cdc.gov/nccdphp/dnpa/bmi/childrens_BMI/about_childrens_BMI.htm
  5. Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States,1999-2004. JAMA. 2006 Apr 5; 295(13):1549-55.
  6. Drewnowski A, Specter SE. Poverty and obesity: the role of energy density and energy costs. American Journal of Clinical Nutrition 2004; 79:6-16.
  7. Daniels SR. The Consequences of Childhood Overweight and Obesity. The Future of Children 2006; 16(1): 47-67.
  8. Wikipedia. Health Belief Model. Wikimedia Foundation. http://en.wikipedia.org/wiki/Health_Belief_Model
  9. Furst T, Connors M, Bisogni CA, Sobal J, Falk LW. Food choice: a conceptual model of the process. Appetite 1996; 26:247-66.
  10. Wong, S. Personal communication. 08 April 2007.
  11. Zenk SN, Schulz AJ, Israel BA, James SA, Bao S, Wilson ML. Neighborhood racial composition, neighborhood poverty, and the spatial accessibility of supermarkets in metropolitan Detroit. American Journal of Public Health 2005; 95:660-7.
  12. Kipke MD, Iverson E, Moore D, Booker C, Ruelas V, Peters AL, Kaufman F. Food and park environments: neighborhood-level risks for childhood obesity in East Los Angeles. Journal of Adolescent Health 2007; 40:325-33.
  13. Wikipedia. Social Cognitive Theory. Wikimedia Foundation. http://en.wikipedia.org/wiki/Social_cognitive_theory
  14. Wikipedia. Transtheoretical Model. Wikimedia Foundation. http://en.wikipedia.org/wiki/Transtheoretical_Model
  15. Wikipedia. Maslow’s Hierarchy of Needs. Wikimedia Foundation. http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs

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