The Protein Leverage Hypothesis and Weight Management in Athletics: An Observational Study

Abstract

Stephen Simpson and David Raubenheimer’s research developed the protein leverage hypothesis, which explains that the amount of carbohydrates and fats consumed in a human diet is lowered greatly when the amount of calories from protein consumed increases slightly. This results in weight loss, which is necessary for athletes in weight-dependent sports. In this observational study we observed the nutritional habits and weights of eleven male collegiate wrestlers along with eight students who do not partake in athletics. Their diets and weights were recorded over the course of thirty days to find the effect of a diet consisting of a high percentage of protein on a subject’s percent change in weight. In a linear regression model we saw a positive relationship between the two variables, with protein percentage having a significant effect on the percent weight loss (p <0.05 for both athletes and non-athletes, but weight loss (p < 0.0001) was greater for athletes even though there was no statistical differences between types of students in terms of calorie intake. Presumably the difference resulted from different levels of energy expenditure associated with training regimes. Given there was no interaction between the main effects (p > 0.84), the study shows that protein leverage impacts weight loss in athletes and non-athletes, and that with exercise greater percent weight loss can be achieved. However, it is important to address that the athlete’s significantly higher consumption of protein also accounts for the additional weight loss observed.