The Effects of Sex Hormones on Food Intake, Body Weight, and Fat Composition: A Cross-Species Analysis

Abstract

Reproductive hormones affect the physiology of eating, body weight, and fat composition differently among the sexes and across multiple species. While the reproductive influences on feeding are known, these studies have been previously limited to just one species in both studies and literature reviews. In addition, discrepancies have also been found across different species. For instance, female mice tend to experience no changes in food consumption whether estradiol is present or not, while female rats experience a decrease in food consumption with the presence of estradiol. The lack of cross-species comparison in these findings leads to a limited understanding of the overall effects of feeding and body composition. Not only are studies limited to one species, but studies are also limited to one sex. Not comparing results to the opposite sex prevents the consideration and realization of the discrepancies in the effects of hormones among the sexes. For example, men with higher levels of testosterone were correlated with healthy Body Mass Index (BMI) levels while women with higher levels of testosterone tend to weigh more than women with normal levels of testosterone. This literature review focuses on inter-species and sex differences of the effects of reproductive hormones on feeding, body weight, and fat composition.