Editorial Comment on: “The Association Between Popular Diets and Serum Testosterone Among Men in the United States”

An estimated 45 million Americans trialed a new diet program in 2018.¹ While restrictive diets frequently yield many positive health outcomes, they can also propagate adverse effects. Fantus et al. analyzed the correlation between diet and serum testosterone (T) levels in a heterogenous, population-based study of 3,128 men using data from the National Health and Nutrition Examination Survey (NHANES) database. The authors report a modest, yet statistically significant, decrease in serum T levels in men following low-fat diets as compared with non-restrictive diets with a mean difference of ~30 ng/dL. The authors propose that low-fat diets decrease serum T levels by providing insufficient nutrients for precursors of steroidogenesis.

Although statistically significant, the clinical significance of the measured decrease in T levels secondary to a low-fat diet remains controversial, particularly in obese males. Pellitero et al.² reported an increase in total T levels of ~300 ng/dL in 33 men following bariatric surgery, supporting the conclusion that significant weight loss in obese males is more beneficial in improving serum testosterone levels overall than a smaller, counteracting decrease in T levels that may result from a low-fat diet. However, in non-obese, otherwise healthy men with hypogonadism, increasing dietary fat consumption may prevent a decline in T levels and may function as an adjunct in a multi-faceted approach of maintaining or increasing serum T levels in this population, which includes a healthy diet and exercise.