Washington, Dec 28 (IANS): If you plan to emulate the diet of plants and animals eaten by our ancestors, remember that it was focused on survival and had little to do with maintaining a balance, a new research suggests.

The Paleolithic or caveman diet likely differed substantially over time and space as our ancestors lived in a wide range of environments, which affected the types of food available.

"There is very little evidence that early humans had very specialised diets or there were specific food categories that seemed particularly important, with only a few possible exceptions," said Ken Sayers, a post-doctoral researcher at the Georgia State University' Language Research Centre in the US.

Also, early humans had shorter life spans so it is difficult to say if their diet was "healthier," he added, wheeas life expectancies are high today, at least in many regions of the globe.

Throughout the vast majority of our evolutionary history, balancing the diet was not a big issue.

"They were simply acquiring enough calories to survive and reproduce. Everyone would agree that ancestral diets didn't include Twinkies (an American snack cake) but I am sure our ancestors would have eaten them if they grew on trees," Sayers said.

According to him, "the foods that we are eating today, even in the case of fruits and vegetables, have been selected for desirable properties and would differ from what our ancestors were eating".

The study examined anatomical, paleo-environmental and chemical evidence, as well as the feeding behaviour of living animals.

The review paper covers earliest hominid evolution, from about 6 million to 1.6 million years ago.

A number of diseases today have been linked with high-fat diets, which have been referred to by some researchers as "diseases of affluence".

They are diseases that come about simply because we are living long enough, the researchers said.

Their findings were published in the journal Quarterly Review of Biology.