I am writing in regards to the article "How much exercise will prevent weight gain?" In it, a study done by a group of Harvard researchers looked to see how much physical activity was needed by adult women to maintain weight loss.
The results of this study are a bit depressing, as it said that women of normal-weight, who exercised one hour per day at a moderate level, did not gain more than five pounds over a three year period, but overweight women who did the same amount of exercise could not prevent weight gain. As a kicker, even normal weight women who got less than seven hours per week of exercise would still gain more weight. How maddening is that?! If a woman is overweight, they gain pounds even if they do workout regularly, and for those who do not do AT LEAST seven hours of exercise per week are basically guaranteed to see increases in their mass.
First, the recommended amount of physical activity for adults is 30-60 per day. Now, that claims to garner cardiorespiratory benefits for people, while not necessarily dealing with weight issues, but it would seem that such benefits would at least help people maintain their weight, not add to it.
Unfortunately, this data coincides with Schoeller (1997), who stated that women, who lost weight, would likely gain 4.5 or more kg during the year following that weight loss, and this also followed the trend that those who started out with less active lifestyles were more likely to gain. The article also comments on the fact that the required amount of physical activity required to maintain weight after weight loss was greater than the amount recommended by Center for Disease Control (CDC). Here, Schoeller claims that the difference in the amount of exercise recommended by the study and the CDC is possibly due to the different goals of each group, with one focusing on weight maintenance and the other aiming to give health benefits.
Another study (Serdula et al., 1999) mentions that two-thirds of adults are trying to lose weight, but that less than a fifth of them are using both reduced caloric intake and 150 minutes per week of exercise. This study seems to contradict the article, stating that the reason why weight loss is so difficult is because people are doing things incorrectly. So, from one study (your article, dear Editor) we are told that losing weight and maintaining weight loss are extremely difficult and made more so due to certain physiological criteria, and from another (Serdula's article), we are told that it is possible to lose weight, but must be done in the correct fashion. This seems to prove the idea that, in researching the human body, if we look around, we can find evidence to support both sides of the same story. How truly frustrating!
Schoeller, D. A., Shay, K., & Kushner, R. F. (1997). How much physical activity is required to minimize weight gain in previously obese women? American Journal of Clinical Nutrition. 66, 551-556.
Serdula, M. K. et al. (1999). Prevalence of attempting weight loss and strategies for controlling weight. JAMA, 282, 1353-1358.