The Influence of Plant- and Animal-Based Diets on Circulating Testosterone and Body Composition of Young Male Rats

Abstract

Within the fitness community there is an unsubstantiated concern that adherence to a plant-based diet results in low circulating testosterone in men, with minimal potential for gains in Lean Body Mass (LBM). We addressed this concern using Long-Evans rats (N=28) assigned to experimental diets of plant (PD) or animal (AD) origin and fed ad libitum for 12 weeks. Animals were further divided into two additional conditions with (E) and without exercise (S). We measured total circulating testosterone and estradiol, and body composition was assessed using dual energy x-ray absorptiometry. Neither totaltestosterone (1.7±0.2 vs. 1.6±0.2 ng·mL-1) nor LBM (384±6 vs. 377±6 g) differed between rats fed the PD or AD diets, respectively, apart from PD+E having higher LBM as compared to AD+E (p=0.03). PD rats were significantly leaner than AD rats, based on body fat (22.4±1.0% vs 32.1±0.8%; p Keywords: Animal Protein; Body Composition; Exercise; Hormones; Plant Protein; Vegan; Western Diet