Middle-aged obese men on a 10-week very low calorie diet lose weight and increase their serum testosterone level but do not see any significant change -- for better or worse -- in their sex life, according to Finnish researchers.

The researchers from Helsinki University Central Hospital compared 19 men who took part in a 4-month weight-loss program including 10 weeks on a very low calorie diet to 19 men who served as a control group. Both groups were followed for a total of eight months.

The mean weight loss for men in the treatment group was more than 40 pounds, and they maintained a weight loss of more than 35 pounds through the end of the eight-month study period, researchers reported in the journal Obesity Research.

But while men in the weight-loss group maintained increases in sex hormone-binding globulin and in testosterone until the end of follow-up, the researchers said there were "no significant changes in the questionnaire scores on sexual function in either group.

"We conclude that obese men lose weight and increase their serum testosterone level on a weight-loss program" with a very-low calorie diet and behavior modification, the researchers concluded. "However, they do not change their sexual function scores."

Other sources: Obesity Research