Why One Size Does Not Fit All Groups of Americans in Efforts to Fight Obesity

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Obesity is a more than $100 billion health care problem that affects almost a third of all Americans, according to the Centers for Disease Control and Prevention. Even more alarming, obesity affects some Americans more severely than others. Some 57% of black women are obese, the highest rate among all racial and ethnic groups.

Research has shown that lifestyle changes through behavioral interventions can produce enough weight losses to lower risks of diseases like type-two diabetes, strokes, and hypertension. Unfortunately, behavioral interventions have proved less effective for black women than for non-Hispanic white women, with blacks on average, losing significantly less weight than whites. In short, black women experience a double burden: Most live with obesity, and benefit less from the standard treatment. To achieve a healthy weight, black women need solutions that meet their needs.

Disparate Gains from Standard Behavioral Weight Loss Interventions

Landmark studies like the Diabetes Prevention Program have produced weight losses in meaningful amounts (5 to 10%) that translate into important health benefits. Successful interventions have three main components: diet, physical activity, and behavior modification.

Unfortunately, black women typically lose significantly less weight than the 5 to 10% goal and do not enjoy the same risk reduction in conditions like type-two diabetes or cardiovascular diseases. This is a long-standing, well-documented trend that is not fully understood. A knowledge gap exists in our understanding of why racial disparities in weight loss persist and how they can be eliminated. My research aims to fill this gap.

Using Physical Activity to Get a Leg Up on Weight Loss

High amounts of moderate-to-vigorous physical activity – some 250 to 300 minutes per week – are recommended for weight loss, and can contribute to a fifth of weight loss when combined with lower calorie intake. Boosts in physical activity are especially important for black women, who nationally have the lowest rates of activity. Recent weight loss studies have highlighted that cultural barriers help explain this deficit – including special issues faced by black women about hair care, body image preferences, and especially demanding multiple social roles. Reducing these barriers not typically addressed in standard behavioral weight loss programs may be the key to improving weight loss outcomes for black women.

My study compared black women participating in a standard behavioral weight loss program to those participating in an enhanced intervention to promote weight loss through culturally-based physical activity components. This program was designed to reduce the unique barriers to physical activity. Women were randomly placed in one of the two groups. Over six months, both groups received the standard intervention where the focus was reducing calorie intake, increasing physical activity, and changing behaviors to lose weight. Those in the enhanced group, however, also received additional program components meant to reduce the impact of activity barriers common to black women. Special components included group physical activity and efforts to feature black women role models who maintain an active lifestyle and have achieved weight loss.

After six months of weight loss interventions, I found, both groups of black women lost about the same amount of weight, a little more than two percent, the typical weight loss result. Furthermore, increases in physical activity did not differ between the two groups. Although this result was unanticipated, it did yield some new insights.

Effective Weight Loss Requires Healthier Environments

It is well established that the current behavioral weight loss approaches do not produce optimal or equal results for black women. Although my study did not increase weight loss, larger environmental reforms could make a difference. These potential steps matter, because they target the environment where individuals can make better choices, enabling black women to achieve health-improving weight losses.

  • Neighborhood improvements could make activity easier and accessible. Reductions in local crime can reduce people’s concerns about whether outdoor activities are safe. Well-maintained sidewalks can also help, and so can access to quality parks and recreational spaces

  • Access to healthy food can improve eating habits. Supermarkets and grocery stores are often few and far between in poor or black neighborhoods, creating healthy food desserts. The presence of food desserts where an overabundance of establishments selling high-calorie fast and low-quality food exist, also limits individuals healthy food options.

The onus for weight loss is often put on the individual even though a person’s environment always plays a key role in their health decisions. My study shows that purely individually targeted efforts aimed at increasing physical activity and healthy eating are not enough.  Improvements for groups vulnerable to obesity, including black women, may require systemic changes – including changes that make environments where physical activity is easier to do and healthy foods easier to obtain. Environmental changes paired with intervention efforts can increase opportunities for black women to engage in healthy weight behaviors. And such changes could have far-reaching benefits for black women and other groups of Americans experiencing obesity.

Read more in Loneke T. Blackman Carr, "Comparative Effectiveness of a Standard Behavioral and Physical Activity Enhanced Behavioral Weight Loss Intervention in African American Women” (forthcoming).