Paleo Diet May Not Suppress Your Appetite: Testing Your Gut Bacteria

Most people have heard about the "paleo" diet, which is supposed to mimic the same diet that early mankind indulged in. Now, scientists are taking a closer look at this diet, and have found that it's not necessarily the appetite suppressor that some people claim it is.

Western diets have changed dramatically in the last century. Currently, these diets are high energy, low fiber, and high fat. Yet our digestive systems, including our gut bacterial colonies, have adapted over millennia to instead process a low-energy, nutrient-poor and presumably high fiber diet. This Western diet has therefore contributed to the current obesity epidemic taking place.

"Getting the bottom of how our gut bacteria and diets interact to control appetites is vitally important for tackling the problem of obesity," said Glenn Gibson, one of the researchers, in a news release.

In this case, the scientists decided to take a look at how a paleo-like diet impacts the colon's microbiota. They created gut bacteria cultures in flasks and then "fed" them two different diets: a predigested potato, high-starch diet or a predigested grass, high-fiber diet. They then tracked the changes in the numbers and types of bacteria.

So what did the researchers find? The cultures on a potato diet produced the highest levels of SCFAs, short-chain fatty acids, which can lead to appetite suppression. In addition, they found that this diet released the appetite-suppressing gut hormone peptide YY (PYY). This in particular is surprising since it shows that the previous view of paleo diets and appetite suppression is flawed; high-fiber, plant based diets likely do not lead to increased SCFAs and increased appetite suppression.

"This hints that protein might play a greater role in appetite suppression than the breakdown of starch or fiber," said Timothy Barraclough, one of the researchers, in a news release. "More work will be needed to explore the effects of alternative breakdown products of various foods."

The findings are published in the journal mBio.