From at least 1.2 million years ago, animal-based foods, particularly meat, were the primary nutritional source for most later hominin lineages, including Homo and Neanderthals, while earlier Australopithecus populations primarily consumed plant-based diets.

Study: Neanderthals, hypercarnivores, and maggots: Insights from stable nitrogen isotopes

This study says Neanderthals might have eaten meat that was already rotten and full of maggots, not just fresh meat — but they still ate animal food, just in a different way. So it still supports the idea that they relied mostly on meat.

Study: Australopithecus at Sterkfontein did not consume substantial mammalian meat.

This study found that ancient ape-like ancestors called Australopithecus ate mostly plants and didn't regularly eat meat, which matches the claim that earlier humans ate plants while later ones like Neanderthals ate more meat.

Study: The diet of the first Europeans from Atapuerca

Scientists looked at tiny scratches on ancient teeth and found they were worn down by tough, crunchy foods—like meat and bone—rather than soft plants. This suggests early humans were eating mostly animal foods, not just plants.

Study: Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus

Scientists found that some ancient humans ate mostly meat, while others ate mostly plants, depending on where they lived. This supports the idea that, overall, later humans relied more on meat than earlier ones did.