Evolution of the human diet

Eduzendium article

The evolution of the human diet is an important research topic within physical anthropology and nutritional anthropology. It involves evidence drawn from human biology, nutritional science, the paleoanthropological analysis of hominin fossil remains, and comparative studies in primatology. Key issues that have been investigated to date include the functional relationship of dentition and craniofacial anatomy to diet, behavioral adaptations to diet (such as the use of tools and fire), the metabolic consequences of increased encephalization, and the relative evolutionary importance of meat-eating. Ancient hominin diets are inferred through a wide range of techniques, such as biomechanics, dental microwear analysis, stable isotope analysis, and paleoenvironmental reconstruction.

Overview

The human diet differs from that of other living primates in several important ways. First, humans are highly omnivorous, exploiting a wide range of plant, animal, and fungal foods (although they do not tend to consume plants high in cellulose, unlike some primates). Second, the human diet is comparatively high-quality, or dense in energy and nutrients. Finally, there is not just one human diet, but instead a very wide range of diets situated within a highly diverse set of environments. Although all humans share the same broad dietary requirements for calories, macronutrients, and micronutrients, various populations have discovered or invented significantly different strategies for meeting those requirements.

Paleoenvironmental reconstruction

The reconstruction of ancient hominin environments provides a valuable foundation for inferring hominin diets, since diets are necessarily shaped and constrained by environmental factors. For example, if an environment is characterized by dry, open grasslands, then it is unlikely that the diet would have contained a large proportion of fruit.

Primatological and ethnographic comparisons

An analysis of extant primate diets can provide clues to the evolution of the human diet, since humans are themselves primates. Additionally, the diet of modern humans living in small-scale foraging societies may be similar to that of the earliest humans.

Morphological evidence

The physical qualities of the masticatory apparatus - teeth, jaws, and related cranial features - can be used to infer the mechanical properties of the foods an organism could or did eat.

Dental morphology and microwear

The size, shape, and configuration of teeth are strongly indicative of diet. Teeth designed to fracture hard, brittle foods, for example, look quite different from those designed for shearing tough, elastic foods. Furthermore, food items often cause microscopic pits and scratches on tooth enamel, and the structure of these features is determined not only by the physical properties of the food, but also by the mechanics of mastication.

Archaeological evidence

Although the archaeological record of early human evolution is quite sparse (especially before 1.8 mya), artififacts can provide valuable dietary evidence. Specifically, the form and wear patterns of early stone tools can suggest how hominins may have gathered and processed various plant and animal foods. Additionally, examinations of the cut marks on preserved animal bones may indicate hominin hunting or scavenging behaviors.

Metabolism and bioenergetics

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