Moderate to Vigorous Physical Activity as a Cause of Dietary Restriction in Eating Disorders

OBJECTIVE: The mechanisms that facilitate prolonged dietary restriction in eating disorders, particularly in the absence of binge eating, remain poorly understood. The activity-based anorexia model and basic science in exercise physiology suggest that moderate to vigorous physical activity leads to reduced energy intake relative to metabolic needs. This reduction in energy intake is even greater when individuals exercise in the fasted, compared to fed, state. METHOD: We propose a model in which moderate to vigorous physical activity facilitates increased dietary restriction within eating disorders. We propose that moderate to vigorous physical activity, regardless of motivation, reduces ghrelin, increases glucagon-like peptide 1 and peptide YY, and reduces food reward. These mechanisms, in turn, contribute to reduced relative energy intake. RESULTS: We review relevant rodent and human literatures to evaluate the model and identify observational and experimental research designs to test these hypotheses. CONCLUSION: Understanding how and when moderate to vigorous physical activity contributes to dietary restriction has important implications for tailoring eating disorder treatment.