Don’t have room for dessert? The bacteria in your gut may be telling you something. Twenty minutes after a meal, gut microbes produce proteins that can suppress food intake in animals, reports a study published November 24 in Cell Metabolism. The researchers also show how these proteins injected into mice and rats act on the brain reducing appetite, suggesting that gut bacteria may help control when and how much we eat.

The new evidence coexists with current models of appetite control, which involve hormones from the gut signalling to brain circuits when we’re hungry or done eating. The bacterial proteins—produced by mutualistic E. coli after they’ve been satiated—were found for the first time to influence the release of gut-brain signals (e.g., GLP-1 and PYY) as well as activate appetite-regulated neurons in the brain.

So maybe it something not even human which tells you to stop eating.