The Claim
Following weight loss in individuals with obesity, postprandial concentrations of satiety hormones (PYY and GLP-1) are lower and concentrations of ghrelin are higher in response to a fixed meal size compared to pre-weight loss levels, resulting in a sustained increase in hunger signaling that promotes weight regain.
What the research says
Roughly balanced
Support and challenge are close. The picture may shift as more studies come in.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
After people with obesity lose weight, their bodies produce less of the hormones that signal fullness and more of the hormone that signals hunger when they eat the same meal they ate before losing weight, which increases hunger and contributes to regaining weight.
See the scientific wording
After weight loss in individuals with obesity, levels of satiety hormones (e.g., PYY, GLP-1) decrease and levels of the hunger hormone ghrelin increase in response to the same meal size, creating a persistent biological drive to eat more and contributing to weight regain.
When fat tissue shrinks after weight loss, the drop in leptin signals the brain that the body is starving. The brain responds by lowering levels of fullness hormones like PYY and GLP-1, raising levels of the hunger hormone ghrelin, slowing down metabolism, and reducing energy use — all to force the body to eat more and regain fat.
What the research says
1 studyStudy: Metabolic and appetitive regulation of adipocyte mass during treatment of obesity
After losing weight, your body tricks you into feeling hungrier and less full after eating, so you’re more likely to eat more and gain the weight back. This is your body’s way of trying to return to its old weight.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.