Mixed
Dietary patterns directly determine gut microbiota composition and metabolic output, with high-fiber/plant-rich diets promoting beneficial SCFA production and low-fat/high-fiber diets increasing Prevotella abundance, while Western diets (high fat/sugar/low fiber) shift the microbiome toward Firmicutes and reduce Bacteroidetes.
Your diet rapidly shapes your gut bacteria. Eating a plant-rich, high-fiber diet (like that of rural populations) promotes beneficial bacteria (Prevotella) and short-chain fatty acids (SCFA) that support gut health. Conversely, a Western diet high in fat and sugar shifts bacteria toward Firmicutes and reduces diversity. To improve your microbiome, prioritize diverse plant fibers and reduce processed fats and sugars, recognizing that your specific response may depend on your current microbial baseline.
Diet is a factor that undoubtedly influences the composition of the intestinal microbiota... Changes in the composition of the gut microbiota in response to dietary intake occur because different bacterial species are better equipped (genetically) to utilise different substrates... The Burkina Faso children had a lower abundance of bacteria of the phylum Firmicutes and a higher abundance of the phylum Bacteroidetes (mainly Prevotella and Xylanibacter)... Muegge et al. found that after just a single day, mice on the 'Western' diet displayed an increased abundance of bacteria of the phylum Firmicutes and a decreased abundance of those of the phylum Bacteroidetes.
Why this rating
Supported by multiple human observational studies (De Filippo, Wu, Zimmer) and controlled animal feeding trials, though large-scale long-term human intervention data is noted as limited.
Source
Intestinal microbiota, diet and health
Susan Power et al. · British Journal Of Nutrition · 2013
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