Sometimes appetite takes over: a bag of potato chips, a second slice of cake or that schnitzel that somehow tastes best at Grandma’s. You keep eating, yet the feeling of fullness doesn’t kick in. Until now, it was only partly understood how the body knows when enough is enough. An international research team has now uncovered an important mechanism behind this – with researchers from Leipzig University involved.
Hunger, craving and cell stress
The study, published in the journal PNAS, focused on a tiny nematode called Caenorhabditis elegans. Unlike mammals, it does not have leptin, the hormone that signals satiety. And yet it reliably regulates how much it eats. How does it do that? The answer lies inside the cell, in a structure called the endoplasmic reticulum (ER), a network of membranes. There, the balance between saturated and monounsaturated fatty acids determines whether the worm keeps eating or stops.
A stress sensor known as IRE-1 detects when this balance is disturbed and triggers a cascade of signals. These signals act via neuronal serotonin and ultimately control two types of hunger: physical need and the desire for pleasure.
