Hadza require diet-derived microbiota-accessible carbohydrates to persist in mice.

Industrialization has transformed the gut microbiota, reducing the prevalence of relative to . Here, we isolate and strains from the microbiota of Hadza hunter-gatherers in Tanzania, a population with high levels of . We demonstrate that plant-derived microbiota-accessible carbohydrates (MACs) are required for persistence of but not . Differences in carbohydrate metabolism gene content, expression, and growth reveal that Hadza strains specialize in degrading plant carbohydrates, while Hadza isolates use both plant and host-derived carbohydrates, a difference mirrored in from non-Hadza populations. When competing directly, requires plant-derived MACs to maintain colonization in the presence of , as a no-MAC diet eliminates colonization. 's reliance on plant-derived MACs and ' ability to use host mucus carbohydrates could explain the reduced prevalence of in populations consuming a low-MAC, industrialized diet.