Vegetarian diets in female athletes: performance, health outcomes, and the implementation gap

Vegetarian diets have gained increasing popularity among athletes, yet evidence regarding their effects in female athletes remains limited. Concerns persist regarding performance, muscle adaptations, hormonal health, and the risk of low energy availability (LEA) and relative energy deficiency in sport (REDs). This narrative review critically evaluates the available evidence regarding vegetarian diets in female athletes, with particular emphasis on health, performance, and physiological outcomes, and the role of dietary implementation in shaping current findings. Available intervention and observational studies generally report comparable performance, physiological, and health-related outcomes between vegetarian and omnivorous diets in female athletes. Accordingly, current evidence does not indicate that vegetarian diets inherently compromise exercise performance, muscular adaptations, hormonal health, or increase REDs risk when nutritional requirements are achieved. However, the evidence base remains limited and heterogeneous. Much of the variability observed across studies may be influenced by implementation-related factors, including energy availability, risk of LEA, protein adequacy, micronutrient intake, dietary quality, and duration of dietary adherence, rather than by dietary classification alone. Collectively, the available literature suggests that health and performance outcomes in female athletes are influenced more by energy availability, nutritional adequacy, and overall dietary implementation than by the exclusion of animal-source foods per se. Future research should improve the characterization of implementation-related factors to support evidence-based recommendations tailored to female athletes.