ITHACA, N.Y. -- The most effective way to curtail the worsening obesity epidemic is to prevent weight gain with small behavioral changes before people become overweight or obese, said James O. Hill, professor of pediatrics and medicine at the University of Colorado Health Sciences Center, speaking at Cornell University, June 6. 

Addressing obesity and energy balance at Cornell's conference, "Ecology of Obesity: Linking Science and Action," Hill stressed that dieting doesn't work: Most people regain lost weight because once a person is overweight, it's more difficult to keep off lost weight. Instead, prevent weight gain in the first place. All it would take, he said, is an additional 2,000 steps -- walking about a mile or 15 minutes -- and 100 fewer calories a day. 

"This is a degree of behavior change that we can actually do," said Hill, director of the Center for Human Nutrition, a nutrition center funded by the National Institutes of Health, and a co-founder of America on the Move, a national weight gain prevention initiative to inspire American communities to adopt these goals. It requires an entire community to support weight gain prevention, he said, and that could include real estate agents, for example, giving clients a free pedometer for buying a house, hotels distributing community maps that indicate how far restaurants are in steps and car dealers offering a year's free pass to a local zoo with each car purchase. 

Hill, whose presentation was prerecorded and delivered via video, was available live via video-link to answer questions. He said that as our population gets fatter each year, "this strategy can prevent about 90 percent of the weight gain." He also noted that those who are succeeding in avoiding weight gain are those eating low-fat diets, not low-carbohydrate diets.

The average American takes about 5,600 steps a day, Hill said, engages in about 10 minutes of physical activity and gains one to three pounds a year. About 65 percent of Americans are overweight or obese, twice the percentage than in the 1980s. 

The conference, sponsored by the College of Human Ecology at Cornell and co-chaired by Christine Olson, professor of nutritional sciences, and Nancy Wells, assistant professor of design and environmental analysis, was video-linked to 10 sites across New York state. Experts also addressed how the built environment influences physical activity, the socio-economic and racial/ethnic disparities in obesity, the life course and obesity, and youth and obesity. On the second day of the conference, researchers and practitioners discussed collaborative community interventions and research priorities.