Nick NorwitzMD PhD, Oxford-Harvard | Metabolic Health Educator | “Stay Curious”

The Weirdest GLP-1 Weight-Loss Paradox

7 Oct 2026 · 1 min

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1:05

In this explanatory monologue, Nick Norwitz highlights a puzzling finding that GLP-1 based weight‑loss drugs, which are known to suppress appetite, paradoxically activate the brain’s hunger‑driving neurons. He describes animal studies where chemically disabling these hunger neurons leads to reduced food intake, yet GLP-1‑treated animals initially lose weight but later regain it aggressively despite continued lower food consumption. Norwitz explains that these hunger neurons possess a secondary function: under GLP‑1 influence they shift substrate utilization from carbohydrate to fat oxidation, mimicking a keto‑like metabolic state. This shift sustains metabolic rate and helps maintain lower body‑fat levels over the long term, offering a potential explanation for the drug’s lasting efficacy despite the apparent paradox.

Chapters

You know what's weird? Researchers just found out that GLP-1 weight loss drugs turn on hunger neurons. Why would a drug that decreases appetite turn on neurons known to drive hunger? It's like pressing the gas to the floor to stop a car. It doesn't make sense. So what's going on and what does this mean? Well, check this out. If you chemically handicap these hunger neurons in animals, The animals do eat less, and the GLP-1 drug does initially cause weight loss, but then the weight yo-yos back aggressively even though the animals kept eating less. It's like you're munching celery sticks, but the belly fat came back with a vengeance anyway. And as it turns out, these hunger neurons have a second nature, and the GLP-1 actually causes them to increase fat burning over carb burning, almost like you're on a keto diet. And it's that effect that keeps metabolism running healthy and keeps body fat down for the long haul.