Carlos Solis
Your gut hosts more than 3,000 bacterial species. We know those microbes help digestion and support immunity. But could they also push us toward certain flavors and dishes — in other words, shape our food preferences?
Microbes as appetite ‘manipulators’
“We don’t always meet our microbes face-to-face,” said Dr. Joe Elcock, a coauthor of the paper and a professor of emergency medicine at the University of New Mexico, to Live Science.
As an example, he pointed to Salmonella Typhimurium. That pathogen hijacks chemical signals between the gut and the brain to keep the host eating during infection. “Normally appetite falls during a gastrointestinal infection,” Elcock said. “But Salmonella seems to disrupt that, so animals keep eating and shed infectious particles in their feces that can infect other animals.”
However, that work was theoretical: it outlined possible mechanisms — for example, changing taste receptors or interfering with the vagus nerve — but it did not prove those manipulations drive everyday food preferences.
Can microbiomes change taste preferences in mice?
In 2022, researchers began testing that hypothesis experimentally. They transplanted microbiomes from wild rodents with different diets — carnivores, herbivores, and omnivores — into germ-free mice and observed what the mice chose to eat.
Researchers expected mice with carnivore microbiomes to prefer a high-protein diet. Instead, mice with herbivore microbiomes favored protein, while mice that received carnivore microbiomes gravitated toward carbohydrates. The key finding was this: different microbiomes produced statistically significant differences in food choice.
How it might work
Gut bacteria can produce many of the same neurotransmitters the brain uses to regulate appetite, including serotonin — a satiety signal. The gut produces about 90% of the body’s serotonin, and studies show the microbiota directly influences that production.
In that experiment, mice that received herbivore microbiomes had much higher blood levels of tryptophan — the amino acid used to make serotonin. Earlier studies found that higher serotonin levels suppress cravings for carbohydrates, which could explain why those mice shifted toward a protein-rich diet.
Brian Trevellin suggested this could be one pathway by which the microbiome influences diet, appetite, and food preferences.
A feedback loop: diet shapes the microbiome, and the microbiome shapes diet
The results also suggest the relationship can go both ways. If the microbiome shapes our cravings and our diet reshapes the microbiome, then even small changes in what we eat can shift that cycle over time.
A key caveat: researchers ran these experiments in mice. Human food choice is complicated. Culture, society, economics, learned habits, and associations all shape what people eat. In short, many factors besides microbiome biology influence our food decisions.
Still, some recent work links these observations to human health. A 2025 study in Nature Microbiology found that the bacterium Bacteroides vulgatus can suppress sugar cravings in mice by producing a metabolite that stimulates production of glucagon-like peptide-1 (GLP-1) — the same hormone targeted by drugs like Ozempic. The researchers also found that this bacterial strain was less common in some human samples.
Cole warned against overreaching conclusions: free will still exists. Microbes do not control our choices. But those cravings — the subtle urges about food — come from our internal nutritional state, including amino acids and other compounds in the blood, and those compounds respond to the microbiome.
So studies suggest the microbiome may be another player in the complex game that determines our food preferences. For now, though, it remains hard to say how much it changes an individual person’s real-world choices.
Photo: Unsplash
