Definition:
An evolutionary hypothesis proposing that humans gained an important energetic advantage by fermenting foods outside the body before consuming them. Fermentation can partially break down complex carbohydrates and other food components, potentially improving digestibility, nutrient availability, preservation, and palatability while reducing some of the metabolic costs of digestion. The hypothesis suggests that external fermentation may have complemented other forms of food processing, including cooking, and may have been particularly important in human evolution because humans lack the extensive internal fermentation chambers found in many other mammals. The hypothesis is particularly associated with David A. S. Lieberman.
