Among women consuming a usual diet, physical activity was associated
with less weight gain over 13 years only among women of normal weight,
according to a new study. The researchers also found that women
successful in maintaining normal weight averaged approximately 60
minutes a day of moderate-intensity activity throughout the study.
The prevalence of overweight and obesity in the United States has
increased dramatically over the past 2 decades, with 1 in 3 adults
currently obese. "Because the average U.S. adult gains weight with age,
developing ways to prevent unhealthful weight gain would help them
avoid having to lose weight and then trying to maintain that loss.
Compared with the vast body of research on the treatment of overweight
and obese individuals, little research exists on preventing weight
gain," the authors write. "The amount of physical activity needed to
prevent long-term weight gain is unclear."