Diet has long been hypothesized as a driver of change among hominins, especially with regard to the increase in brain size. However, identifying diet in early hominins has been difficult because of the diagenic loss of organic matter in collagens older than 200,000 years.

Lüdecke et al. looked at carbon and nitrogen isotopes bound to tooth enamel in fauna from an approximately 3.5-million-year-old site that includes several Australopithecus fossils.

Dietary niches reconstructed based on these fossils showed that the Australopithecus individuals had diets very similar to both contemporaneous and modern herbivores but different from carnivores.

Thus, consumption of meat in these early hominins did not pave the way to humanizing traits such as larger brains.