In Korean adults, the integration of gut microbiome data with plant-based diet indices enhances the predictive accuracy for obesity and elevated fasting glucose relative to plant-based diet indices alone, while clinical markers maintain higher predictive performance, indicating that microbiome profiles provide complementary information regarding diet-related metabolic risk.

When people eat mostly whole plant foods like fruits, grains, and legumes, good bacteria in the gut break down fiber to make butyrate, which strengthens the gut lining and reduces inflammation, helping the body use insulin properly and store less fat. When people eat lots of refined sugars and white bread, bad bacteria grow and release toxins that leak into the blood, causing inflammation and making the body resistant to insulin, which raises blood sugar and increases fat storage. These microbial changes explain why combining gut bacteria data with diet info predicts obesity and high blood sugar better than diet alone.