Listen up, fellas. According to research presented at the 23rd European Congress of Endocrinology, a low-calorie ketogenic (keto) diet has been shown to improve sex hormone levels in overweight and obese men.
In the first study of its kind, investigators from Italy examined the potential effects this eating pattern could have on weight loss, along with testosterone and sex hormone levels called sex hormone-binding globulin (SHBG) since obesity can lead to low testosterone (typical symptoms of which include low sex drive and difficulty getting an erection). In order to test this theory, the authors instructed 17 overweight or obese men who didn't have diabetes to follow an 800-calorie-a-day keto diet for four weeks. Tests were performed before and after the one- and four-week marks of the study.
At the end of the study, the participants showed a significant decrease in body weight, fat mass, and body mass index (BMI), as well as a "substantial increase" in total testosterone and SHBG levels. The medical researchers say their findings have shown a link between insulin action, energy balance, and testicular function.
Obesity remains a national and global epidemic. The World Health Organization reports that obesity rates around the globe have tripled since 1975. According to the latest statistics from the Centers for Disease Control and Prevention (CDC), obesity affects approximately 42% of adults in the U.S. and is one of the leading causes of premature—and preventable—deaths from various chronic conditions, including heart disease, stroke, type 2 diabetes, and certain types of cancer.
"The aim of this study was to assess the effect a low-calorie ketogenic diet had on a group of subjects affected by morbid obesity. Therefore, a typical keto diet wouldn't allow a remarkable weight loss as we expect from a low-calorie approach," lead researcher Angelo Cignarelli, MD, PhD, assistant professor in the section of internal medicine, endocrinology, andrology, and metabolic diseases at the University of Bari Aldo Moro, Italy, tells Eat This, Not That!
He explains it's well-understood that fat mass—particularly visceral adipose tissue (defined as a type of fat that surrounds the organs) is associated with a reduction of testosterone level, which is referred to clinically as functional hypogonadism. "Moreover, hypogonadism is responsible itself for abdominal fat mass gain dragging subjects in a sort of vicious cycle reducing exercise and energy expenditure."
Dr. Cignarelli also quickly points out this low-cal eating plan is a very temporary situation.
"The low-calorie ketogenic diet should be considered as a short-term nutritional intervention able to induce a rapid fat mass loss," he continues. "Thus, even recognizing the value of higher-rated eating plans [such as the Mediterranean diet, the DASH diet, or the Flexitarian diet] which should be followed at the end of a short-term nutritional treatment, we aimed to assess the possibility to give a boost in terms of weight and fat loss and testosterone levels in the short term in order to support the patients in such a difficult context, like morbid obesity."
However, if your BMI is in the obese range, keep in mind it's important that you don't try this super-low-calorie version of the keto diet (or any diet for that matter) without a doctor's supervision.
"Let me put this into perspective: According to the U.S. Department of Agriculture, 800 calories per day is the recommended daily amount for a 12- to 23-month-old baby to eat!" says Dawn Jackson Blatner, RDN, CSSD, author of "The Superfood Swap: The 4-Week Plan to Eat What You Crave Without the C.R.A.P."
"In fact, it's a set up for failure since it is unrealistic to maintain that low level of calories. And, even more importantly, an adult male is not able to get all of the recommended nutrients for a healthy body at that calorie level."
Looking ahead, Dr. Cignarelli and his team plan on digging deeper into the keto-testosterone connection. "Whether the effect obtained from this approach is sustained by calorie restriction or by ketosis—or both—is not yet established. Further studies will clarify this point."
Now, be sure to check out This One Thing Could Be Sabotaging Your Weight Loss Success, New Study Says