The diet of our prehistoric ancestors consisted of 80 percent red meat and 20 percent fruits and vegetables, two new studies revealed.

The findings support the idea that at least some paleo diets, which were presumably eaten by ancient humans, relied greatly on red meat, included a few fruits, vegetables and some plant materials, and mostly excluded seafood.

Led by Hervé Bocherens from the University of Tübingen, researchers from Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) performed isotopic analysis on the skeletons of early humans from Asia and Europe. The team also looked at the diet of Stone Age Homo sapiens.

"We have taken a detailed look at the Neanderthals' diet," said Bocherens.

Bocherens said they were able to find out that the extinct relatives of modern humans primarily ate large herbivorous animals.

He and his colleagues examined the remains of Neandarthals and animals from two excavation sites in Belgium. They contrasted the diets of prehistoric humans to the diets of woolly rhinoceroses, mammoths, reindeer, wild horses, European bison, cave hyenas, lions, bears and wolves.

It was assumed that ancient humans used the same food sources as these animals, but the study revealed that all predators occupied a very specific niche. Predators preferred smaller prey, but Neanderthals specialized on plant-eaters such as mammoths and woolly rhinoceroses.

Scientists have also found ancient weapons such as spears that are associated with Neanderthals. This meant the prehistoric group must have had a very organized approach to hunting large prey.

While Neanderthals were meat-eaters, they also consumed vegetables, fruits and other plants. Bocherens said they were able to determine the proportion of vegetarian food in the diet of late Neanderthals. Similar findings were found from Stone Age humans, he said.

Meanwhile, the team hopes that further studies could shed light on what could have led to the disappearance of Neanderthals and their way of life. Modern humans' cultural advances may have driven our prehistoric cousins to extinction, according to a previous study. In any case, it appears the Neanderthals were not starving to death based on their eating habits.

"We are accumulating more and more evidence that diet was not a decisive factor in why the Neanderthals had to make room for modern humans," added Bocherens.

The findings are featured in the Journal of Human Evolution and the journal Quaternary International.