Losing weight may have a surprising benefit for middle-aged men. A study of nearly 900 men at risk of type 2 diabetes compared the effects of diet and exercise in one group, metformin in another group and a placebo control in the third group. Both metformin and lifestyle changes were able to delay the onset of type 2 diabetes.
In addition, however, men who controlled their blood sugar with diet and exercise were much less likely to have low testosterone. At the beginning of the study, 20 percent of them had low levels of this important hormone. After a year of lifestyle modification that resulted in weight loss, only 11 percent had low testosterone. This male hormone is related to muscle and well-being as well as to sexual interest and performance. There was no change in the incidence of low testosterone in either of the other two groups.
[The Endocrine Society’s 94th Annual Meeting in Houston, June 25, 2012]