The paleo or “caveman” diet, which essentially involves eating unmodified foods that would have been available 15,000 or so years ago, has gained steam in recent years. But a new study might knock down one of the diet’s prevailing theories.

Some believe the increase in obese individuals these days is due to our food not matching the low-energy, high-fiber diet humans ate thousands of years ago. Thus, the ability to suppress one’s appetite isn’t functioning like it should.

Researchers found the contrary: paleo diets, at least the high plant fiber part, don’t necessarily suppress one’s appetite.

In test tube, the scientists compared how gut microbes of human vegetarians and of grass-eating baboons digest food. The hormones that help suppress appetite the, peptide YY and glucagon-like-peptide-1, a news release about the study stated, can be triggered by short-chain fatty acids, which is produced by the fermentation of plant fibers by bacteria in the colon. That said, it would be assumed that a high plant fiber diet might lead to less of an appetite.

“Getting to the bottom of how our gut bacteria and diets interact to control appetites is vitally important for tackling the problem of obesity,” Glenn Gibson, co-author on the study based at University of Reading, said in a statement. “Understanding how a paleo-like diet impacts the colon’s microbiota and the signals those bacteria produce to release hormones that reduce appetite may give us new insight that we can adapt in the modern world.”

Bacteria obtained from human or baboon sources were fed either a potato, a high-starch or predigested plant fiber diet. Scientists then measured the production of short-chain fatty acids. Both types of bacterial samples produced more of these compounds on a potato diet. Scientists confirmed that the compounds produced by these bacteria could trigger the hormones to be produced by testing it in mice.

With these findings, researchers think that higher plant-based diets might have the opposite effect on appetite suppression.

“This hints that protein might play a greater role in appetite suppression than the breakdown of starch or fiber,” Timothy Barraclough, another co-author of the study, said. “More work will be needed to explore the effects of alternative breakdown products of various foods.”

Most paleo diets do include a greater source of protein, which could contribute to appetite suppression and thus a reduced caloric intake and weight loss.

This study was published in the journal for the American Association for Microbiology.

(H/T: Science Daily)