“Messed-up gut” may describe post-infectious sensitivity, IBS-like irregularity, or diet–stress driven irritation. The core goal is a stabilizing plan that reduces barrier stress. Step one is a 7–14 day simplification: cut ultra-processed foods, heavy fried fats, high sugar, heavy alcohol, and excessive caffeine. Step two: gradually add “gentle fibers” such as oats, well-tolerated starches (rice/potato), vegetable soups/purees, and bananas. Step three: keep protein and electrolytes steady (yogurt/kefir if tolerated, eggs, fish, legumes). Step four: optimize sleep and stress—gut symptoms often amplify when sleep is poor. If diarrhea dominates, prioritize hydration and salt balance. Persistent symptoms (especially beyond 4 weeks, weight loss, bleeding, or nighttime diarrhea) require evaluation for organic causes. Supplements are not a substitute for structure: consider a goal-matched probiotic/postbiotic as a measurable 2–4 week trial. Long-term success comes from sustainable eating patterns and trigger management.