Do GLP-1s reduce hunger, or do they just slow food leaving the stomach?
Updated: 2026-09-09 · GLP-1 and weight
Short answer
Both are described. GLP-1 receptor agonists slow gastric emptying, so food stays in the stomach longer, and they also act on brain regions involved in appetite and satiety. The two mechanisms coexist, and how much each contributes varies between molecules and between people.
In plain English
- Slower gastric emptying: fullness that lasts longer after eating.
- Central signalling: less appetite and less constant food preoccupation, as described in the literature.
- The gastric-emptying effect appears to attenuate over time in several studies.
- It also explains why digestive complaints are the most frequently reported adverse effects.
What we know
- The GLP-1 receptor is expressed both in the digestive tract and in appetite-related brain regions.
- Labels for approved medicines in this class describe delayed gastric emptying.
What we don't know yet
- How much each mechanism contributes to the outcome in any individual.
- Why the size of the effect varies so widely between people.
Mechanism description for educational purposes. It is not usage guidance and does not replace a healthcare professional.