It might reasonably have been expected that the adoption of cooking by early humans would not have led to any changes in human digestive anatomy. After all, cooking makes food easier to eat, which means that no special adaptations are required to process cooked food. However, current evidence suggests that humans today such efficiency, we suggest, led to an inability to survive on raw-food diets in the wild.
Important questions therefore arise concerning what limits the ability of humans to utilize raw food. The principal effect of cooking considered to date has been a reduction in tooth and jaw size over evolutionary time. Human tooth and jaw size show signs of decreasing approximately 100,000 years ago; we suggest that this may prove to result from later modifications in cooking technique, such as the adoption of boiling.
The evolution of soft parts of the digestive system is harder to reconstruct because they leave no fossil record. Human digestive anatomy differs from that of the other great apes in ways that have traditionally been explained as adaptations to a high raw-meat diet. Differences include the smaller gut volume, longer small meat. Testing between the cooking and raw-meat models for understanding human digestive anatomy is therefore warranted.
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