High-protein diets and testosterone

Abstract

A recent meta-analysis found low-carbohydrate, high-protein diets (> 3.4 g/kg of bodyweight/day) (g/kg/day) decreased men's total testosterone (∼5.23 nmol/L) [Whittaker and Harris (2022) Low-carbohydrate diets and men's cortisol and testosterone: systematic review and meta-analysis. Nutrition and Health. DOI: 10.1177/02601060221083079]. This finding has generated substantial discussion, however, it has often lacked clarity and context, with the term ‘high-protein’ being used unqualified. Firstly, diets < 3.4 g/kg/day are not associated with a consistent decrease in testosterone. Secondly, the average protein intake is ∼1.3 g/kg/day, conventional ‘high-protein’ diets are ∼1.8–3 g/kg/day and the vast majority of athletes are < 3.4 g/kg/day; meaning very few individuals will ever surpass 3.4 g/kg/day. To avoid such confusion in the future, the following definitions are proposed: very high (> 3.4 g/kg/day), high (1.9–3.4 g/kg/day), moderate (1.25–1.9 g/kg/day) and low (<1.25 g/kg/day). Using these, very high-protein diets (> 3.4 g/kg/day) appear to decrease testosterone, however high- and moderate-protein diets (1.25–3.4 g/kg/day) do not.

Sarcopenia and Diabetes: A Detrimental Liaison of Advancing Age

“…A mild but significative reduction in serum testosterone has also been observed with the Mediterranean diet [ 80 ]. Conversely, a low-carb diet with moderate-to-high protein intake not exceeding 3.4 g/kg/day is usually associated with a neutral or even ameliorating effect on serum testosterone [ 81 , 82 , 83 ]. Very low-carb diets induce a significant increase in serum testosterone, even if the magnitude of this effect is strictly associated with weight loss and the patient’s age [ 84 ].…”

Obesity, Dietary Patterns, and Hormonal Balance Modulation: Gender-Specific Impacts

“…A recent cross-sectional study conducted on 125 Taiwanese men reported that greater adherence to a typical high-calorie WD was associated with a decrease in testosterone levels by 0.87 ng/mL [ 136 ]. Furthermore, a recent meta-analysis by Whittaker and Harris [ 137 ] revealed that very-high-protein diets (>3.4 g/kg/day) are associated with a decrease in men’s total testosterone levels by approximately 5.23 nmol/L. This suggests that adopting hyper-protein diets for weight loss or muscle mass gain might be counterproductive, potentially adversely affecting testosterone levels.…”