The evolution of diet within hominins is considered an essential aspect of their adaptive mechanism. The rise in basal metabolic rate that characterizes human beings required a significant increase in the quantity of calories ingested. We have several tools at our disposal to study the diet of extinct forms. Comparative dental anatomy has historically been the first of these. Microscopic stigmata (impacts and striations of enamel wear) left on the surface of dental crowns during mastication provide a second, which has been considerably enhanced by image analysis techniques. However, it is geochemistry that has most recently been used to address this issue. For recent prehistoric periods, stable isotopes of carbon and nitrogen extracted from organic matter make it possible to distinguish trophic chains and locate an individual's place within them. In earlier times, strontium and barium isotopes were used to assess the level of meat consumption. Today, it is mainly studies on zinc isotopes, which, like their predecessors, are fixed in the mineral part of skeletal remains, that seem the most promising.
Chimpanzees, the sister group to hominins, include a meat component in their diet, derived from hunting. This is generally relatively small, and varies from one individual or population to another. It is therefore very likely that this behavior also existed in the earliest forms of hominins. It was only around two million years before the present that predatory or scavenging behaviour developed in a spectacular fashion. From this time onwards, their traces become abundant in the archaeological record. The development of cooking, at least on an optional basis, marked another important stage in this evolution. Generally speaking, food preparation (grinding, cutting, cooking, etc.) increased energy intake while reducing the physiological cost of chewing and digestion. Although the hunting of large mammals played a central role in the dietary strategies of Middle and Upper Pleistocene mankind, we must not overlook plant resources which, depending on the environment, may have represented an important contribution.
