Rather than focusing on long-term correlations between diet and microbial composition, the study asked whether the adult human gut microbiome could shift within days in response to sharply contrasting diets.
The researchers placed 10 volunteers each on two controlled dietary interventions: an animal-based diet composed of meats, eggs and cheeses, and a plant-based diet rich in grains, legumes, fruits and vegetables.
They then tracked microbial composition, gene expression and metabolic output.
They found that the gut microbiome responded rapidly and reproducibly, with the strongest taxonomic shift observed on the animal-based diet.
These changes showed that diet can quickly alter both the ecological structure and functional state of the gut microbial community.
What does it mean to say that we are shaped by what we eat? The 2014 paper by Lawrence David and colleagues published in Nature provided a framework in which this question could be tested experimentally. Rather than focusing on long-term correlations between diet and microbial composition, the study asked whether the adult human gut microbiome could shift within days in response to sharply contrasting diets.
The researchers placed 10 volunteers each on two controlled dietary interventions: an animal-based diet composed of meats, eggs and cheeses, and a plant-based diet rich in grains, legumes, fruits and vegetables. They then tracked microbial composition, gene expression and metabolic output. They found that the gut microbiome responded rapidly and reproducibly, with the strongest taxonomic shift observed on the animal-based diet. Within days, the animal-based diet increased bile-tolerant microorganisms such as Alistipes, Bilophila and Bacteroides, while decreasing Firmicutes (now termed Bacillota) that metabolize dietary plant polysaccharides, including Roseburia, Eubacterium rectale and Ruminococcus bromii. These changes showed that diet can quickly alter both the ecological structure and functional state of the gut microbial community.
