Comp Biochem Physiol A Mol Integr Physiol. 2003 Sep;136(1):35-46

'Cooking as a biological trait'

Wrangham R, Conklin-Brittain N.

Department of Anthropology, Harvard University, Peabody Museum, 11
Divinity Avenue, MA 02138, Cambridge, USA

No human foragers have been recorded as living without cooking, and
people who choose a 'raw-foodist' life-style experience low energy and
impaired reproductive function. This suggests that cooking may be
obligatory for humans. The possibility that cooking is obligatory is
supported by calculations suggesting that a diet of raw food could not
supply sufficient calories for a normal hunter-gatherer lifestyle. In
particular, many plant foods are too fiber-rich when raw, while most raw
meat appears too tough to allow easy chewing. If cooking is indeed
obligatory for humans but not for other apes, this means that human
biology must have adapted to the ingestion of cooked food (i.e. food
that is tender and low in fiber) in ways that no longer allow efficient
processing of raw foods. Cooking has been practiced for ample time to
allow the evolution of such adaptations. Digestive adaptations have not
been investigated in detail but may include small teeth, small
hind-guts, large small intestines, a fast gut passage rate, and possibly
reduced ability to detoxify. The adoption of cooking can also be
expected to have had far-reaching effects on such aspects of human
biology as life-history, social behavior, and evolutionary psychology.
Since dietary adaptations are central to understanding species
evolution, cooking appears to have been a key feature of the environment
of human evolutionary adaptedness. Further investigation is therefore
needed of the ways in which human digestive physiology is constrained by
the need for food of relatively high caloric density compared to other
great apes.

PMID: 14527628