Smithsonian.com

Ghrelin has no resemblance to this gremlin, courtesy of Flickr user inti

Scientists have known for several years now that people are partly controlled by the gremlins and goats in their stomachs…

Pardon me, I mean ghrelin, the so-called “hunger hormone” that triggers appetite when it interacts with fatty acids in the stomach, and GOAT, the enzyme that facilitates that interaction. (But when I’m really hungry, I could swear there are a few of those other creatures kicking around in my belly, too!)

Until now, it’s been assumed that the fatty acids which activate ghrelin are something the body produces when we’re not eating, meaning that hunger is inevitably triggered by an empty stomach. Turns out that may not be the case, however. Instead, it seems to be ingested dietary fats that activate ghrelin—in other words, eating a deep-fried Twinkie may actually make you hungrier! (Or, to put it visually…)

This twist comes from a new study in the journal Nature Medicine, conducted by the University of Cincinnati’s Matthias Tschöp and other scientists. Their findings “turn the current model about ghrelin on its head,” at least according to the press release.

Reporting evidence that “ghrelin is acting more as a meal preparation cue than as a hunger cue,” the study’s authors posit that “GOAT-ghrelin system acts as a nutrient sensor by using readily absorbable [fatty acids] to signal to the brain that highly caloric food is available, leading to optimization of nutrient partitioning and growth signals.”

The study was conducted in mice, so it’s premature to draw conclusions about humans from it, but the possibilities are intriguing in terms of treating metabolic disorders and obesity.

It may also explain why gastric bypass surgery is so successful in curbing appetite, as Tschöp notes: “This procedure causes food to bypass the stomach and gut sections that contain GOAT/ghrelin cells, which, based on this newly described model, would prevent ghrelin activation.”

I think my gremlin wants salad for lunch today.