Key Points 3 – Influence of Athletic Diet on Gut Microbiota.

• Diet is an established modulator of gut microbiota composition and activity, with marked changes in microbiota composition evident within 24 h of a dietary change.

• Energy balance is currently an overlooked factor in relation to the athletic gut microbiota, particularly in those affected by RED-S.

• To solely investigate the impact of total energy consumption without considering dietary variability is difficult (if not impossible).

• The effects of high-protein consumption (without concurrent high-fat) on gut bacteria are not well studied. This also includes the effects of high-protein and high-fiber intake.

• Protein intake appears to be a strong modulator of microbiota diversity, with protein supplementation, such as whey, showing potential benefits that need further study in humans.

• Proteins from vegetable origin have a marked effect on gut microbiota but currently require investigation in athletes.

• In future studies, the types and amounts of fats consumed in conjunction with protein should be investigated in the overall effect on the gut microbiota.

• Increased intake of dietary fiber is associated with microbial richness and/or diversity.

• Higher intake of carbohydrate and dietary fiber in athletes appear to be associated with increased abundance of Prevotella.

• The specific effects of fat on the gut microbiota is difficult to isolate; however, the types of fats consumed appear to be important.