Friday Nov 08, 2013 (foodconsumer.org) -- Calorie restriction can help increase the serum concentration of the male sexual hormone testosterone in obese men, according to a study most recently published  in Hormone and Metabolism Research.

D. M. Schulte from University of Kiel in Kiel, Germany and colleagues conducted the study and found caloric restriction increased the serum concentration of testosterone through two mechanisms, improving testicular function and reducing the conversion of testosterone into β-estradiol in adipose tissue.

The concentration of serum testosterone is largely regulated by the testicular function and once produced, a certain amount of testosterone is converted into β-estradiol by adipose tissue, the authors explain in their report.  

For the study, researchers asked 13 obese men with a median body mass index of 43 kg/m2  to use a very low calorie diet containing only 800 kcal per day for a period of 12 weeks.

They found that calorie restriction significantly increased the total serum testosterone and sex hormone-binding globulin.  Also, the increase in the serum testosterone was coupled with a significant improvement of the testicular function and a significant decrease in the T/β-estradiol conversion rate.

The researchers concluded "In obese men caloric restriction significantly increases the serum testosterone concentration. This is achieved by 2 distinct mechanisms, that is, improvement of testicular function and reduced conversion of testosterone to β-estradiol by aromatase activity of the adipose tissue."

Calorie restriction can provide a range of health benefits including chronic disease prevention and extended lifespan among other things. (David Liu PHD)