Exercise Feeds Good Bacteria

Athletes tend to carry a richer mix of gut bacteria than sedentary people of similar age and diet. Exercise reshapes gut bacteria on its own, separate from any diet change, and the bacterium Akkermansia muciniphila — linked to leaner body composition — rises in people who stay active.

These microbes may even carry part of the benefit themselves: mice given bacteria from active donors showed better insulin sensitivity without exercising, hinting that exercise works partly through the bugs it nurtures.