Investigating the Impact of Dietary Practices on Female Athletes' Health and Performance: A Comparative Analysis of Keto, Plant-Based, Intermittent Fasting, and Western Diets

Female athletes face unique physiological challenges, particularly concerning energy availability, hormonal balance, and menstrual health. This research aims to compare the effects of four distinct dietary practices—keto, plant-based, intermittent fasting, and the Western diet—on female athletes' performance, recovery, and overall well-being. Central to this investigation are key considerations such as energy availability, carbohydrate timing, and nutrient timing, all of which play critical roles in preventing Relative Energy Deficiency in Sport (RED-S) and its associated consequences, including amenorrhea and reduced bone density. 

The study will evaluate the benefits and limitations of each dietary approach. Plant-based diets, while rich in essential nutrients like magnesium, and omega-3 fatty acids, may pose challenges in meeting protein, Iron and B12 requirements, increasing the risk of RED-S. Conversely, high-fat, low-carb diets like keto have shown promise in fat loss and mental focus but may disrupt hormonal function and menstrual health, particularly during the adaptation phase or when energy intake is insufficient. The research will also address the role of strategic carbohydrate timing in mitigating these risks. 

Intermittent fasting, characterised by defined eating windows, presents unique challenges for female athletes, as prolonged fasting can disrupt kisspeptin and leptin levels, essential for menstrual regularity. Insufficient caloric intake during eating periods may exacerbate the risk of RED-S. In contrast, the Western diet, often high in refined sugars and processed foods, may lead to metabolic issues if not carefully managed. However, with appropriate energy intake and nutrient balance, it can support performance without significantly increasing the risk of RED-S. 

This comparative analysis will incorporate both quantitative and qualitative data, examining health metrics, hormonal profiles, menstrual regularity, athletic performance metrics, and subjective well-being among athletes adhering to these diets.  A key focus will be on identifying dietary patterns that optimise performance while safeguarding hormonal health. Findings from this research aim to inform evidence-based dietary recommendations tailored specifically for female athletes, emphasising the importance of individualised nutrition strategies in mitigating RED-S and promoting long-term health and athletic success. 

This PhD project offers a significant opportunity to address critical gaps in sports nutrition research, ultimately contributing to enhanced dietary guidelines and better health outcomes for female athletes across various sports disciplines. 

To apply for this project, please submit an application for October 2025 entry at this link (How to apply for a research degree (PhD, Professional Doctorate, MPhil, MA/MSc by Research) - Kingston University London) and ensure that you upload a document as part of your application that states you are applying for a studentship and the name of the project that you are applying for.