The slim edge
How important is exercise for women who just want to maintain their weight?
Researchers at Harvard Medical School studied data accumulated between 1992 and 2007 from 34,079 healthy women with an average age of 54 who were on a “usual diet.” The women’s levels of activity were divided into low (under 7.5 hours a week), medium (7.5-21 hours a week), and high (more than 21 hours a week). Overall, the women’s average weight gain over the 13 years of the study was an insignificant 2.6 kilos. Significantly, however, the weight gain depended on the women’s initial body mass index (BMI) at the start of the study. Women with a starting BMI below 25 who averaged one hour per day of moderate-intensity exercise gained less than 2.3 kilos over 13 years. The overweight (BMI 26-30) or obese (BMI over 30) at the start of the study showed no benefit from exercise. The study’s conclusion for women? You can maintain normal weight with a good amount of exercise. But once you become overweight, exercise becomes less effective in helping maintain your weight.