Full intestines, more than full stomachs, may tell mice to stop eating

Bulging stomachs often take the blame for ending holiday indulging. But bulging guts might be the real appetite killer, a study in mice suggests.

The results, published November 14 in Cell, could point out new ways to treat obesity, or even help explain how gastric bypass surgeries limit eating. Those procedures result in food moving faster through the stomach into the intestines, stretching the gut in a way that might signal fullness, the authors speculate.

Zachary Knight, a neuroscientist at the University of California, San Francisco, and colleagues identified and studied nerve cells in mice’s intestines that sense mechanical stretching. To simulate full intestines, the team activated these nerve cells with light and chemicals. As a result, the mice ate less food. Physically stretching the mice’s intestines with a salty liquid or a diuretic also caused the mice to eat less.

Different stretch-sensing cells in the stomach also curbed mice’s appetites, but to a lesser extent, the researchers found.

These nerve cell endings relay messages up the vagus nerve (SN: 11/13/15), which then zips signals to the brain. These messages about intestinal stretching help influence the eat-or-not decision, researchers suspect.