Bad Gut Bacteria Could Sabotage Your Weight Loss Resolution


‘Tis the season for losing weight and getting healthy, the No. 1 New Year’s resolution in America for 2017, according to NBC News.

Although many diet plans promise the moon as far as immediate results, conventional wisdom has long held that a healthy, balanced diet chock full of fruits and vegetables is the true gateway to better health. So why does it take so long to lose pounds when you go that route? A new study provides some answers.

According to research recently published in Cell Host & Microbe, changing your diet all at once – even to a plant-rich, nutrient-dense, low-calorie diet – may not offer immediate health benefits. That’s because the microbiota, the bacteria that live inside your gut, may lose some members that came from the “bad diet.” And in fact, you need some of those bacteria, even if they came from the “bad diet,” to maintain optimal health.

There still appear to be ways you can get more diverse gut bacteria, but probably not if you live alone.

In their experiment, researchers from Washington University in St. Louis took fecal samples from people who had followed a calorie-restricted, plant-rich diet, as well as samples from those who had been on a typical, unrestricted American diet. They found that those who followed the plant-rich diet had more diverse gut microbiota.

They then colonized the guts of germ-free mice (meaning their guts were a “clean slate” as far as microbiota goes) with microbiota from the standard American diet or the plant-based diet. Next, they fed them either a standard American diet or a calorie-restricted, plant-based diet.

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While both groups eventually had health positive responses to the plant-based diet, the mice colonized with microbiota samples from humans on the standard American diet took longer to do so. But when researchers began to stage encounters between the mice with the plant-rich diet microbiota and those with the standard American diet microbiota, results began to improve for those on the plant-rich diet but with the standard diet microbiota. This was because microbiota migrate from person to person (or mouse to mouse) within living environments, such as family homes.

Helicobacter pylori (yellow), a common bacteria found in the stomach lining, Credit: Martin Oeggerli/Flickr

“The microbiota of an individual is not an isolated community, but rather exists within a large metacommunity, in which microbes have the potential to disperse between people to colonize new gut habitats and to become locally extinct from others,” the researchers wrote.

“The current study illustrates a way of characterizing the extent to which bacterial dispersal under the most permissive conditions (cohousing of coprophagic mice) impacts diet responses,” they concluded. “An artificial metacommunity provides an opportunity to mine multiple human microbiota for organisms that are not only reporters of responses to diet interventions but also effectors of host responses to these interventions.”

In other words, the next step is for researchers to determine how microbiota from a “bad diet” could kick-start the benefits of a “good diet” in the form of supplements taken during the diet transition. The key, of course, will be determining exactly how all the different microbiota interact for optimum health.

Related: Canada’s ‘Poop Lady’ on Gut Health: It’s All in the Stool

A professional journalist nearly 30 years, David Heitz started his career at the Quad-City Times in Davenport, Iowa before moving to Los Angeles. He led the Glendale News-Press to best small daily newspaper in the state (CNPA) as managing editor and also worked as executive news editor of the Press-Telegram. He worked briefly as deputy news editor of the Detroit News before returning to the Quad-Cities, where he has worked as a freelance medical writer since 2012 for several national websites. He recently purchased his childhood home and says he truly is “living the dream.”