Following a low-fat diet may result in reduced testosterone levels in men, and eating more fat may help boost borderline-low testosterone levels, according to a new analysis published in The Journal of Steroid Biochemistry and Molecular Biology.
Past research has linked certain dietary factors — such as a diet high in processed and red meat, refined grains, and sugar — to impaired testicular function and a lower sperm count in men. Because a diet high in refined carbohydrate and processed and red meat is often high in total fat, researchers were interested in what role, if any, total fat consumption might have on testosterone levels in men. Testosterone is the primary sex hormone in men, produced by the testicles, and plays a role in key health-related traits like muscle and bone mass, in addition to its role in sexual function.
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For the latest analysis, researchers looked at studies that compared the effects of following two different eating patterns — one low in fat, and one high in fat — on testosterone levels in men. To be eligible, a study had to be randomized — meaning that participants didn’t know which diet they would be following when they enrolled in the study, and were randomly assigned to follow one diet or the other. The researchers found six eligible studies, with a total of 206 participants.
Low-fat diet linked to testosterone drop
Overall, the studies showed that eating a low-fat diet led to a significant drop in testosterone and related sex hormones. Compared with a high-fat diet, following a low-fat diet resulted in an average decrease in total testosterone of 38%. It also led to a 37% drop in free testosterone (testosterone not yet absorbed by cells, circulating freely in the blood) and a 38% drop in urinary testosterone. This consistent drop in all measurements makes it highly likely that a drop in testosterone production — rather than a change in how testosterone is used in the body — was the result of a low-fat diet. A stronger effect on testosterone levels was seen in European and North American men than in other geographic or ethnic groups in the study, with this subset of men seeing a 52% drop in total testosterone as a result of following a low-fat diet.
The researchers concluded that based on a limited number of small studies, it appears that following a low-fat diet leads to significantly reduced testosterone levels in men, especially European or North American men. These results suggest that out of all of the elements of a typical Western diet — a pattern of eating linked to worse testicular function — a higher level of fat probably isn’t what’s contributing to testicular problems. Instead, refined grains and sugars, and processed foods in general, are more likely to blame for problems in testicular function linked to an unhealthy diet.
More studies with more participants are needed, the researchers noted, to confirm that following a low-fat diet leads to lower testosterone levels than following a high-fat diet.
Want to learn more about testosterone in type 2 diabetes? Read “Exercise Beats Testosterone for Blood Vessel Health in Men,” “Testosterone Therapy Linked to Lower Type 2 Risk in Men,” and “Testosterone for Type 2 Diabetes?”
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