A population-based strategy needed to tackle obesity in U.S.

Jul 1 2008

A comprehensive, population-based strategy is needed to reduce the alarming prevalence of obesity in the United States, according to a new American Heart Association scientific statement published in Circulation: Journal of the American Heart Association.

"Population-Based Prevention of Obesity" recommends an approach that would complement individually-oriented strategies, including clinic-based prevention and treatment programs. According to the statement, a broad range of policy and environmental strategies (at the local, state and federal levels) can help people adopt healthy behaviors, such as being physically active and eating right.

"Almost all of our current eating or activity patterns are those that promote weight gain - using the least possible amount of energy or maximizing quantity rather than quality in terms of food," said Shiriki Kumanyika, Ph.D., R.D., M.P.H., chair of the working group that wrote the statement. "People haven't just made the decision to eat more and move less; the social structure has played into people's tendencies to go for convenience foods and labor-saving devices."

Preventing weight gain should be easier, socially acceptable and more rewarding for the average person, she said, noting that "passive," whole-population approaches - through environmental and policy changes - could increase opportunities for healthful eating and physical activity without requiring deliberate action by individuals, and can also help address inequalities.

"We're not talking about creating a dieting society, but looking at choices people make in day-to-day living that affect their ability to manage their weight and then trying to change the environment to facilitate healthier choices," said Kumanyika, a professor of epidemiology at the University of Pennsylvania School of Medicine in Philadelphia.

Modifying the environment to affect people's choices includes assessing the following areas to identify targets for change:

• Locations of fast-food restaurants
• Restaurant portion sizes
• Availability of high-fat, low-fiber foods and sweetened drinks
• Community design and infrastructure, which involves assessing land use mix and "walkability" of neighborhoods, including -
  • Adequate sidewalks and areas for physical activity
  • Accessibility of jobs, schools, and recreation by walking or cycling
  • Availability of public transportation

"The concept of population-level interventions to change contexts for individual behavior is well known from the experience with tobacco regulations," Kumanyika said.

"Changes in these areas can eventually become 'normal' and displace the current 'normal' ways of doing things," she said. "Right now, you have to be pretty single-minded to make some of these choices, such as walking or riding a bike instead of driving. We advocate changes that will move the social norm to where physical activity is the custom."

About 67 million American adults are obese, and an additional 75 million are overweight, according to the 2001-04 U.S. National Health and Nutrition Examination Survey (NHANES). About 4.2 million children 6-11 years old and 5.7 million adolescents (age 12-19) are also overweight.

Kumanyika said there have been dire projections about how many children will ultimately become obese if the same trends continue. The most recent national survey data, released in May 2008 (JAMA 2008 May 28;299(20):2401-5) reported no significant changes in the proportion of children and adolescents who are overweight or obese were observed between 2003-04 and 2005-06.

"This could be good news-a sign that recent public health efforts in raising awareness of childhood obesity are working-but it's really too soon to tell," she said. "Regardless, childhood obesity must remain on the population health agenda for years to come. We need much more than a plateau. We need a reversal."

While treatment for obesity-related conditions, such as type 2 diabetes, high blood pressure and high cholesterol, is crucial to reducing risk factors for cardiovascular disease and improving overall disease management, it cannot curb the epidemic, the writing group said. "The increase in Type 2 diabetes is a striking example of why preventing obesity is so important," said Kumanyika.