Your gut can change in just u003ca href=u0022https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3957428/u0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003e2–4 daysu003c/au003e of eating the right foods. It might take a few more weeks for the stomach to create a new lining, but that’s only with consistent dieting. People who have food sensitivities or autoimmune conditions may need to wait longer for gut changes.