The bacteria in your large intestine live mostly on fiber you cannot digest yourself. When they ferment it, they produce short-chain fatty acids that feed the cells lining your gut and help keep that lining intact. Most American adults eat roughly half the fiber recommended, and a diet built on ultra-processed food feeds a narrower range of bacteria. Diversity commonly drops, and a less diverse community is often the one behind the gas, the irregularity and the reactions to foods that never used to bother you.
Sleep and stress push on the same system from a different direction. Short or broken sleep and a stretched month shift appetite toward quick, low-fiber choices and change how the gut moves food along, which is why a stressful week so often shows up as a bloated one. A course of antibiotics clears helpful bacteria along with the target, and the community can take weeks to months to rebuild. Movement works the other way: regular activity is associated with healthier gut motility and diversity.
The gut also talks to the rest of you. Absorption decides what reaches your skin, which is why our skin and longevity support program in Charlotte, NC includes gut health as one of its three levers, and why our registered dietitian is the lead resource on this page rather than a supplement shelf.
