A large, community-based study – considered the first study to assess the long-term risk of developing overweight and obesity in adults – found that over 30 years, nine out of 10 men and seven out of 10 women were overweight or became overweight. In addition, more than one in three were obese or became obese. The study was supported by the National Heart, Lung, and Blood Institute (NHLBI), one of the National Institutes of Health (NIH).

Researchers analyzed the short-term and long-term chances of developing overweight and obesity among more than 4,000 white adults enrolled in the offspring cohort of NHLBI's landmark Framingham Heart Study, an ongoing longitudinal study in Framingham, Massachusetts. Participants ages 30 to 59 were followed for 30 years, from 1971 to 2001. The results appear in the October 4, 2005, issue of the Annals of Internal Medicine.

“National surveys and other studies have told us that the United States has a major weight problem, but this study suggests that we could have an even more serious degree of overweight and obesity over the next few decades,” said NHLBI Director Elizabeth G. Nabel, M.D., who also co-chairs the NIH Obesity Research Task Force. “In addition, these results may underestimate the risk for some ethnic groups.”

Framingham participants were white, and other studies have shown, for example, that Hispanic and black individuals, especially women, have a greater prevalence of excess weight compared to their white counterparts.

According to the National Center for Health Statistics, part of the Centers for Disease Control and Prevention, 65 percent of U.S. adults aged 20 years and older are either overweight or obese, and approximately 30 percent of adults are obese. These estimates are from the 1999-2002 National Health and Nutrition Examination Survey, a population-based survey.

Framingham researchers assessed the participants’ body mass index (BMI) – a standard measure of weight relative to height, which is an indicator of total body fat. A BMI of 18.5 to 24.9 kg/m2 is considered a normal, or healthy, weight for adults. Overweight is a BMI of 25 to 29.9 kg/m2, and obesity is a BMI of 30 kg/m2 or higher.