How do I improve my gut microbiome diversity?

Reduce consumption of ultra-processed foods (UPFs), particularly those containing emulsifiers like carboxymethylcellulose (CMC) and polysorbate 80 (P80). Check ingredient lists for these additives.

Center your diet around vegetables, fruits, whole grains, legumes, nuts, olive oil, and fish. Limit red meat, refined grains, and added sugars. This is not a rigid diet but a flexible eating pattern.

Cook starchy foods (potatoes, rice, pasta) and then cool them in the refrigerator before eating. Reheating is fine — the resistant starch structure persists.

Eat polyphenol-rich foods daily: berries, dark chocolate (70%+), green tea, coffee, red/purple grapes, and colorful vegetables.

Increase your daily fiber intake to the recommended 25g (women) to 38g (men). Most Americans eat only about 15g/day. Add fiber gradually — 5g per week — to avoid bloating.

Include at least one serving of fermented food daily: yogurt with live cultures, kefir, unpasteurized sauerkraut, kimchi, miso, or kombucha.

Aim to eat 30 or more different plant types each week. "Plants" includes fruits, vegetables, whole grains, legumes, nuts, seeds, herbs, and spices — each one counts as a separate type.