Exercise and dietary extremes significantly impact gut microbial diversity. This study examined professional rugby athletes and compared them with control groups to assess the effects of exercise and diet on gut microbiota. Athletes showed higher gut microbial diversity, representing 22 distinct phyla, which positively correlated with protein consumption and creatine kinase levels. The results suggest that exercise enhances gut microbiota diversity, but the relationship is complex and influenced by accompanying dietary extremes. Athletes had a more favorable metabolic and inflammatory profile compared to controls, with higher proportions of the genus Akkermansia in the low BMI group. Dietary protein intake was significantly linked to microbial diversity, and protein-rich diets were associated with increased gut microbial diversity. The study highlights the importance of diet and exercise in shaping the gut microbiota, which plays a role in health and disease. Further research is needed to understand the mechanisms and optimize therapies targeting the gut microbiota.Exercise and dietary extremes significantly impact gut microbial diversity. This study examined professional rugby athletes and compared them with control groups to assess the effects of exercise and diet on gut microbiota. Athletes showed higher gut microbial diversity, representing 22 distinct phyla, which positively correlated with protein consumption and creatine kinase levels. The results suggest that exercise enhances gut microbiota diversity, but the relationship is complex and influenced by accompanying dietary extremes. Athletes had a more favorable metabolic and inflammatory profile compared to controls, with higher proportions of the genus Akkermansia in the low BMI group. Dietary protein intake was significantly linked to microbial diversity, and protein-rich diets were associated with increased gut microbial diversity. The study highlights the importance of diet and exercise in shaping the gut microbiota, which plays a role in health and disease. Further research is needed to understand the mechanisms and optimize therapies targeting the gut microbiota.