You know a rumbling tummy is a sign you haven’t eaten in a while. But there’s a lot more going on down there than a quaking plea for more food.
Like street sweepers cleaning up after a parade, the gastrointestinal contractions you feel are your gut’s way of cleansing your empty stomach of left-behind food particles, bacteria overgrowth and other debris, says Dr. Toku Takahashi, a professor and gastroenterologist at the Medical College of Wisconsin.
Takahashi says the rumbling is just one phase of a larger process called the migrating motor complex (MMC), which ensures your stomach and intestines stay active and continue to clear away detritus between meals. He says a poorly functioning MMC has turned up in patients with abdominal pain, nausea, vomiting and other symptoms of indigestion or the presence of harmful microorganisms.
Aspects of your gut’s grumbling may also affect your risk for weight issues like obesity.
Feelings of hunger come from your brain, but they’re based on chemicals signals your brain receives from your gut, says Dr. Jan Tack, a professor of medicine who studies gastrointestinal disorders at Belgium’s University of Leuven. According to Tack, there’s mounting evidence that both hunger and the different phases of the MMC are triggered by a “forgotten” gut hormone called motilin.
“The hormone is ‘forgotten’ because rats and mice do not express it, so it is under-studied,” Tack explains.
Gut chemistry quickly gets complicated. But Tack says both obesity and hunger appear to be linked in some ways to your motilin levels. “We have shown that motilin-induced hunger signaling is altered in people experiencing unexplained weight loss and obesity,” he says.
Tack says a person’s motilin levels also seem to change after bariatric procedures like gastric bypass surgery. Motilin may also affect the ways you experience pleasure or a sense of reward after eating, he adds.
All of this research is very new. But manipulating motilin and the resulting MMC response may eventually emerge as a novel way to treat obesity, dyspepsia and other gut-related health issues, Tack’s research suggests.
In the meantime, one thing is certain: It’s normal and healthy to experience a grumbling stomach in between meals.