If you temporarily gain - and then lose - even a small amount of fat, does your body return to how it was before gaining? A recent study by researchers at the Mayo clinic found that in fact the body does not return to its pre-gain composition and that weight is not lost in the same pattern that it was gained. For this study, researchers had 15 men and 8 women in their 20’s and 30’s increase their weight by 5%. Depending on energy needs, subjects were given one, two, or three of the following each day: a 400-calorie ice-cream shake, a 510-calorie king size Snickers bar, or a 360-calorie cup of Boost Plus.
After eight weeks of being overfed, the body composition of subjects was assessed. Subjects averaged a gain of about seven pounds of fat and one pound of muscle. 61% of the extra fat, on average, was upper-body subcutaneous (fat just below the skin), 12% was visceral (fat deposited around the internal abdominal organs), and 27% was lower-body (primarily hips and buttocks).
Next the subjects were prescribed calorie restricted diets and additional exercise to lose the weight gained. After eight weeks, subjects had lost an average of five pounds. Thus, subjects were able to gain weight faster than they were able to lose it. Also, weight that was put on in the lower body decreased less than abdominal weight, so that the process of weight gain and then weight loss caused subjects to retain more weight in the lower body.
Consistent with previous studies, the researchers found that when participants gained weight the number of fat cells in their body increased. However, when they lost weight, the additional fat cells decreased in size but remained at increased numbers. One disadvantage of having additional fat cells, especially when they lose stores, is that each cell produces hormonal signals that increase hunger levels. This study points to the fact that once weight is gained, even if it is eventually lost, the body does not return to its original leaner state.
What to do: Aim to prevent weight gain by consuming a healthy diet, getting regular activity, and monitoring your weight. Because after weight loss we retain extra fat cells that produce hunger signals, it is more challenging to maintain lost weight than it is to maintain a healthy weight. This does not mean maintaining loss is impossible but that sticking with the healthy behaviors you have acquired during weight loss is key to long-term weight loss maintenance.
Adapted from article in Nutrition Action Healthletter, Sept. 1, 2012, pg 8.
Source: Singh P, Somers V, Romero-Corral, et al. Effects of weight gain and weight loss on regional fat distribution. Am J Clin Nutr; July 3, 2012, doi: 10.3945/ajcn.111.033829 available at http://ajcn.nutrition.org/content/early/2012/06/28/ajcn.111.033829.full.pdf
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