Meeting Abstract

P2.99  Jan. 5  Testing the selective advantage to cooking in human evolution BOBACK, S.M.*; COX, C.L.; OTT, B.D.; CARMODY, R.; WRANGHAM, R.W.; SECOR, S.M.; University of Alabama sboback@ua.edu

The cooking of food has been proposed to have played a pivotal role in human evolution, responsible for the development of numerous morphological, physiological and social traits. Compared to raw meat, cooked meat is potentially easier to eat, requiring less time and energy for processing and digesting. We tested the hypothesis that cooking and chewing of meat decreases the energy expended on digestion using the Burmese python. Pythons were fed one of four experimental diets each weighing 25% of snake body mass; raw intact steak, cooked intact steak, ground raw steak, and ground cooked steak. We measured oxygen consumption rates of snakes prior to and up to 14 days following feeding. Meal treatment had a significant impact on the postprandial peak in oxygen consumption, the scope of peak rates, and specific dynamic action (SDA, the metabolic cost required to breakdown, absorb, and assimilate a meal). Snakes digesting the raw intact meals exhibited a significantly larger postprandial metabolic response, increasing rates of oxygen consumption by as much as 14-fold above fasting rates, whereas snakes digesting the cooked ground meals experienced significantly smaller responses (10-fold increase in metabolism). On average, cooking decreased the overall cost of digestion (SDA) by 12.7% and the grinding of meat (raw or cooked) decreased SDA by 12.3%. These findings demonstrate that cooking, and thus the tenderizing of meat, provides energetic advantages over a raw diet, evidence to support the claim that cooking has had a significant impact on human evolution.