Exercise and Weight Loss: More Tough News for Women

Exercise alone does not seem to be effective in preventing weight gain once a woman is already heavy. The latest issue of JAMA reports on a huge study trying to see if different levels of exercise prevent weight gain in women.

Exercise alone does not seem to be effective in preventing weight gain once a woman is already heavy. The latest issue of JAMA reports on a huge study trying to see if different levels of exercise prevent weight gain in women. This study looks at the 34,000 women in the Women’s Health Study, a huge cohort of women which has already reported on aspirin use and other variables. The results are not encouraging. Regular exercise was only associated with lack of weight gain in women who were thin (BMI<25) at the start of the study. Women who ranged from upper normal weight (BMI 25-30) to obese (BMI >30) gained weight even if they exercised regularly. The only group of women who did not gain weight over the 13 years of follow up in the study were thin women who exercised regularly for 60 minutes daily of moderate to high intensity exercise. The take-home messages of this study are:

  1. Starting early with prevention of obesity is key. Once overweight it is far more difficult to prevent further weight loss. Multiple prior studies have demonstrated how difficult it is to achieve sustained weight loss.
  2. Calorie restriction is needed to prevent weight gain once overweight. Exercise alone is not sufficient.

The conclusion of this study sums it up pretty well:

“In conclusion, in this large prospective study of women consuming a usual diet, sustained moderate-intensity physical activity for approximately 60 minutes per day was needed to maintain normal weight and prevent weight gain. These data suggest that the 2008 federal recommendation for 150 minutes per week, while clearly sufficient to lower the risks of chronic diseases, is insufficient for weight gain prevention absent caloric restriction. Physical activity was inversely related to weight gain only among normal-weight women; among heavier women, there was no relation, emphasizing the importance of controlling caloric intake for weight maintenance in this group.”

Ed Pullen, MD, is a board-certified family physician practicing in Puyallup, WA. He blogs at DrPullen.com — A Medical Bog for the Informed Patient.

This article originally appeared online at DrPullen.com.