The problem with following a calorie-restricted diet during middle age is the muscle loss. However, a study presented at the Endocrine’s Society’s annual meeting on April 2 reveals that taking testosterone reduces fat without causing muscle loss fat in obese middle-aged men on a diet.

Overall, the men who took testosterone lost 11 kilogrammes without losing muscle mass. Moreover, these men lost three kg more body fat than those who did not receive testosterone. The researchers studied 100 obese men with ages 20 through 70 years.  These men have low testosterone levels and 20 percent of them have diabetes while 10 percent have heart disease.

The team divided these participants into two groups, administering 1000 milligrammes of testosterone to 49 men intramuscularly while injecting placebo to the other 51 men every 10 weeks over the study period. The team placed these participants on a strict low-calorie diet for the initial 10 weeks, eating only 600 kcal daily.

taking testosterone

Testosterone reduces fat without causing muscle loss fat in obese middle-aged men following a calorie-restricted diet. Photo from Pixabay/Wadams

The researchers also prohibited these men from drinking alcohol and encouraged them to exercise moderately for at least 30 minutes daily. After the 10th week, these men ate normal foods based on the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) Total Wellbeing Diet until the study’s 56th week.

Both groups lost 11 kg at the end of the experiment. Those who were in the testosterone group lost mostly fat and maintained their muscle mass but those in the placebo group lost 3.5 kg of muscle mass, proving that taking testosterone reduces fat without causing muscle loss even if people are on a very low-calorie diet.

“There is an epidemic of obesity and related functional hypogonadism, yet testosterone treatment remains controversial,” adds associate professor in the Department of Medicine at the University of Melbourne in Victoria and principal investigator Mathis Grossmann. “This study shows for the first time that, among obese men with lowered testosterone, testosterone treatment augmented the diet-induced loss of total and visceral fat mass and prevented the diet-induced loss of lean mass.”