A 2021 study has shown that a ketogenic diet can boost testosterone levels in obese men as they lose fat.

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A low-calorie ketogenic diet is just what Thor needs to get back into killer shape

How a Ketogenic Diet Can Restore Testosterone Levels in Obese Men

New research which is yet to be published has shown that a low-calorie ketogenic diet can help overweight men lose weight effectively and increase their testosterone and sex hormone (SHBG) levels.

Worldwide, obesity nearly doubled between 1980 and 2008. According to the CDC, 42% of adults were classed as obese in 2017-18, up from 30% in 1999-2000. As if it needs saying, obesity is a leading cause of other serious conditions including heart disease, the number-one killer worldwide, strokes, type 2 diabetes and certain forms of cancer. The estimated annual medical cost of obesity in the United States was $147 billion in 2008 US dollars, and the medical cost for people who have obesity was $1,429 higher than those of normal weight. (US statistics – CDC)


Obesity is also a leading cause of hypogonadism, or low testosterone levels, in men, a phenomenon we have examined in great detail in a series of articles. As well as having serious repercussions for individual physical and mental health in men, the current crisis of low testosterone is also a societal crisis.

It is now being predicted by at least one leading expert on fertility that if current trends continue, the majority of men will be totally infertile by 2045, and the remainder functionally infertile. One of the main causes, in addition rising levels of obesity and inactivity, appears to be growing exposure to xenoestrogenic chemicals, which mimic the effects of estrogen in the human body. Atrazine, the second most-popular herbicide in the US, is one such chemical.

During the new study, 17 male subjects were fed a diet consisting mostly of fat, with little protein and very few carbohydrates. Total daily calories were less than 800. A diet of this kind has previously been found to reduce body weight, glycaemia and insulinemia, but its effects on total testosterone and SHBG levels had not been properly investigated until this point. 

The team from the University of Bari in Italy investigated whether this same calorie-restricted ketogenic diet would also have a positive effect on total testosterone and SHBG levels. It’s worth noting that as well as being responsible for sexual and reproductive functions, testosterone is known to play a role in energy use and metabolism, so the hypothesis was plausible prima facie.

If you’re interested in learning more about the master male hormone, including ways you can boost your levels, download our FREE new ebook now.

The subjects underwent a low-calorie ketogenic diet for four weeks, and various tests were carried out before and after one and four weeks. Body weight, fat mass and body mass index (BMI) significantly decreased and a substantial increase of total testosterone and SHBG levels also took place. 

Said Dr Angelo Cignarelli, the team leader: 

We aimed to evaluate the response of total testosterone and sex hormone levels to a very low-calorie ketogenic diet in a cohort of overweight or obese non-diabetic male subjects and what we found was that there is a noticeable relation between a specific, controlled diet and insulin action, energy balance, and testicular function.”

How a ketogenic diet can change your life for the better

This study has highlighted once again the close relationship between insulin action, energy balance, and testicular function. In two recent articles, we’ve talked about the close relationship between insulin sensitivity and testosterone levels. One study has shown that having diabetes can reduce your testosterone levels by as much as gaining 20lbs of fat, while another showed that testosterone replacement therapy could reduce the risk of diabetes significantly.

Check out these 6 easy ways to boost testosterone levels without spending a penny.

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