time, and part environment. In the case of human brain evolution, the main environmental influence was adaptation to a 'shore-based' diet, which provided the world's richest source of nutrition, as well as a sedentary lifestyle that promoted fat deposition. Such a diet included shellfish, fish, marsh plants, frogs, bird's eggs, etc. Humans and, and more importantly, hominid babies started to get fat, a crucial distinction that led to the development of larger brains and to the evolution of modern humans. A larger brain is expensive to maintain and this increasing demand for energy results in, succinctly, survival of the fattest.

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