When people talk about gut health, they often jump straight to probiotics, skipping over the foundation — feeding existing gut microbes a wide selection of plant foods. A variety of plants offer different fibers, resistant starches, and polyphenols that fuel beneficial microorganisms and support a diverse, resilient microbiome. In recent years, scientists have revealed a simple yet powerful guideline for boosting your gut microbiome — aim for at least 30 unique plant foods each week.