Regulatory foods support natural bowel rhythm through fiber, water, and bioactive compounds. For constipation-prone patterns: oats, psyllium, prunes, kiwi, flax/chia, legumes, vegetable soups, plus adequate fluids are often effective. For diarrhea-prone patterns, soluble fibers (oats, banana, applesauce, potato) can help firm stool. Fermented foods (kefir/yogurt) may support regularity if tolerated. Diversity matters: overloading one fiber type can cause bloating; spreading different sources in smaller portions often improves tolerance. Fat quality matters too—olive oil may support smooth passage, while excessive fat can worsen diarrhea in some. Also consider micronutrients: magnesium, vitamin D, B12, and iron status can influence bowel patterns. The biggest gains come when foods are part of a structured routine—fiber across the day, steady hydration, and regular movement.