Biology

Scientists Discover That Binge-Eating Sweet Treats Is Influenced by Gut Microbiome

Many Oreo Cookies

According to new California Institute of Technology (Caltech) research in mice, specific gut bacteria may suppress binge eating behavior.

Gut Microbes Influence Binge-Eating of Sweet Treats in Mice

We have all been there. You just meant to have a single Oreo cookie as a snack, but then you find yourself going back for another, and another. Before you know it, you have finished off the entire package even though you were not all that hungry to begin with.

But before you start feeling too guilty for your gluttony, consider this: It might not be entirely your fault. Now, new research in mice shows that specific gut bacteria may suppress binge eating behavior.

Oreos and other desserts are examples of so-called “palatable foods”—food consumed for hedonistic pleasure, not simply out of hunger or nutritional need. Humans are not alone in enjoying this kind of hedonism: Mice like to eat dessert, too. Even when they have just eaten, they will still consume sugary snacks if available.

The new Caltech study demonstrates that the absence of certain gut bacteria causes mice to binge eat palatable foods. In fact, the findings show that mice with microbiotas disrupted by oral antibiotics consumed 50 percent more sugar pellets over two hours than mice with normal gut bacteria. When their microbiotas were restored through fecal transplants, the mice returned to normal feeding behavior.

Further, the study revealed that not all bacteria in the gut are able to suppress hedonic feeding, but rather specific species appear to alter the behavior. Bingeing only applies to palatable foods; mice with or without gut microbiota both still eat the same amount of their regular diet. The findings show that the gut microbiota has important influences on behavior and that these effects can be modulated when the microbiota is manipulated.

Illustration of the human gut microbiome. Gut microbiota are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tract.

A paper describing the research was published on November 29 in the journal Current Biology. Graduate student James Ousey led the study in the laboratory of Sarkis Mazmanian, the Luis B. and Nelly Soux Professor of Microbiology.

“The gut microbiome has been shown to influence many behaviors and disease states in mouse models, from sociability and stress to Parkinson’s disease,” Mazmanian says. “The recent appreciation that feeding behaviors, driven by motivation, are subject to the composition of the gut microbiome has implications not just to obesity, diabetes, and other metabolic conditions but perhaps to overuse of alcohol, nicotine, or illicit substances that bring pleasure.”

To examine how the gut microbiota influenced feeding behaviors, Ousey gave a group of mice antibiotics for four weeks, wiping out the animals’ gut bacteria. He then compared their feeding behavior to normal mice with a healthy gut microbiota. The two groups ate about the same amount of their standard mouse diet, called chow.

Sarkis Mazmanian. Credit: Caltech

But the real difference was in how much palatable, or dessert-like, food the mice consumed. When presented with high-sucrose pellets, the antibiotic-treated mice ate 50 percent more pellets over two hours and ate in longer bursts than their healthy mouse counterparts.

Ousey then aimed to determine how much effort the mice were willing to expend to obtain sugary snacks. In another set of experiments, instead of simply having treats placed in their cages, the mice needed to push a button to receive a pellet. Each subsequent pellet required the mice to push the button more and more times. The untreated mice, at some point, would lose interest in pushing the button and wander away. However, the mice given oral antibiotics expended much more effort to obtain more and more sugar, pressing the button repeatedly as if desperately craving a snack.

Importantly, this binge eating behavior is actually reversible: The researchers could return the mice back to normal feeding behavior simply by restoring the mouse microbiota through a fecal transplant. The restored mice still consumed sugar when available but did not exhibit the same overeating behavior.

The gut microbiota contains hundreds of bacterial species, and the team suspected that some were more influential than others in driving the binge eating behavior.

“To tease out which specific microbes might be involved, I gave different cohorts of mice different antibiotics individually,” Ousey explains. “The different antibiotics target different bacteria. What I observed was that mice given either ampicillin or vancomycin, but not neomycin or metronidazole, overconsume these high-sucrose pellets compared to controls. That would suggest that there’s some microbe, or some collection of microbes, that is susceptible to either ampicillin or vancomycin, which is responsible for controlling the normal response to the highly palatable foods.”

The team then identified that increased levels of bacteria from the family S24-7 (a type of bacteria specific to lab mice) and from the genus Lactobacillus were associated with reduced overconsumption. When these bacterial species were given to the antibiotic-treated mice, but not other bacteria, hedonic feeding was suppressed.

Though the study only draws conclusions about the mouse microbiota, it opens up new directions of study for understanding how and why we may be driven to overconsume sugary snacks. “I think it would be so intriguing to see if people given oral antibiotics exhibit differences in their eating patterns and dietary choices, and whether these things can be associated with the gut microbiota,” says Ousey. “We know that humans with eating disorders like binge eating disorder and anorexia nervosa have differences in their gut microbiota compared to humans that are not diagnosed with these conditions. Obviously, perhaps the eating disorder affects the microbiota because they’re eating different foods; perhaps it’s bidirectional. But investigations into how antibiotics might affect the responses to palatable foods in humans are definitely doable.”

“We do not understand the neurobiology underlying the observation that the microbiome impacts overconsumption of palatable foods in mice,” says Mazmanian. “Future studies in our lab and others will explore the gut-brain axis in modulating reward circuits in the brain as well as possibly devising probiotics to intervene in eating disorders.”

Reference: “Gut microbiota suppress feeding induced by palatable foods” by James Ousey, Joseph C. Boktor and Sarkis K. Mazmanian, 29 November 2022, Current Biology.
DOI: 10.1016/j.cub.2022.10.066

In addition to Ousey and Mazmanian, graduate student Joseph Boktor is a co-author. Funding was provided by the National Science Foundation, the Gates Millennium Scholars Program, and the Heritage Medical Research Institute. Sarkis Mazmanian is an affiliated faculty member with the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech.

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        • Delusional? When Trump was Pres. we were prosperous and not into a war. Biden gave us inflation, high interest rates, war, border crisis, energy crisis, more wasteful spending on green, more lies and corruption in gov. departments, more moral decline. Facts, not delusion. Wake up.

    • I work in the endoscopy department as a RN. We do fecal transplants every so often, specifically for people who have had C. Diff. It’s basically where you inject a donors fecal matter (their poop: which has healthy bacteria) into the person who does not have healthy gut bacteria. What we are trying to accomplish with this transplant is to replace someone’s bad gut bacteria with the donors healthy gut bacteria.

  • Well it is about time.we started looking more closely at gut flora.
    The Alt Med people have been saying it for several decades.

    Anything that goes against prescribing antibiotics was considered nuball territory.

    P S - what effects do vaccines have on our gut flora?

  • This explains something I just experienced. While on antibiotics, for pneumonia, I was confused by the fact that I wasn't hungry and nothing sounded good, but any type of sugar consumed was insatiably good, like overwhelmingly so. Antibiotics completed and sugar is back to it's normal ho-humness.

  • This is true. Coming from a junk food junkie, I love sweets. But I consume them more when my gut Flora is either off track or just absent period. I just did 10 days of antibiotics. I knew that if I ate sweets anytime during my treatment, I could get a yeast infection. I had no gut flora, no good bacteria to ward off the bad bacteria that was just consumed also. I ate yogurt 2 or 3 times a day with every dose I consumed. The results of that is that I'm not consuming sweets as I normally would devour them because they were apart of my daily life. I'm going to get probiotics today... Renew life woman probiotics are phenomenal and they are great roughly about .54 a capsule but soooooooooo worth it. 16.75... Something like that. These things are amazing when consumed with TONS OF WATER. I drank a gallon a day to make sure I get my gut flushed. Im 200lbs so half my body weight is what I drank. Probiotics will get the gut microbiomes on track for sure.

  • It's hard to believe most scientists because of all the wishy washy stuff about covid and what caused it didn't cause

  • Prior to a fecal transplant,there was an orange fecal abortion that became president 45!!! Still trying to stink up the world....

  • I wonder if even when not directly taking antibiotics,if eating animals like say chicken and beef that were usually given antibiotics could still cause this "binge eating for palatable foods..."

  • It's intriguing but almost impossible for the average person to act on. We're all taking tons of antibiotics by necessity, but the solution to this is a fecal transplant? Who's going to bother?

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California Institute of Technology

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