Although humans cannot digest cellulose like ruminant animals, certain fibers are fermented by gut bacteria into short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate.
Modest Energy Contribution: SCFAs provide a small but meaningful amount of energy—up to 5–10% of daily caloric intake in fiber-rich diets.
Butyrate for Gut Health: Butyrate fuels colonocytes, supports gut barrier integrity, and reduces inflammation.

Synergy with Low-Carb Diets: While ketogenic diets are lower in fiber, including low-carb vegetables and resistant starches can support SCFA production and benefit gut and metabolic health.