The weight you lose on Ozempic isn't all fat. The part that isn't is the problem.

The clinical results for GLP-1 drugs like semaglutide are not in dispute. People lose significant weight on them. In the trials, participants shed an average of around 15% of their body weight, which is more than any previous pharmaceutical approach had managed. The headlines were justified, to a point.

What the headlines were less clear about was what the trials actually tested. Participants in the major semaglutide studies weren't simply handed a prescription and sent home. They received structured dietary advice, a specified eating plan, and regular lifestyle coaching alongside the medication. That context rarely made it into the coverage, and it matters, because the drug and the support programme produced those results together, not separately.

What the drug is actually doing

GLP-1 is a naturally occurring hormone that regulates blood sugar, slows digestion, and suppresses appetite. The medications mimic its effects at doses significantly higher than the body produces on its own. The result is reduced hunger, slower gastric emptying, and better control of blood glucose. For someone whose appetite regulation has been dysregulated for years, the relief is real.

The problem is that the drug is managing the symptoms of that dysregulation, not addressing what caused it. The appetite-regulating systems in the brain haven't changed. When the medication stops, they're still not working properly, and hunger returns, often more intensely than before. One hypothesis, from researchers at the University of Surrey, is that sustained exposure to pharmacological doses of GLP-1 may suppress the body's own production of the hormone, leaving people in a deficit when they come off. The evidence is preliminary, but the bounceback data is not: most people regain around two thirds of the weight they lost within a year of stopping.

The composition problem

Weight lost on GLP-1 drugs is not purely fat. A meaningful proportion, somewhere between 20 and 40% depending on the study, is skeletal muscle. Muscle loss at that scale has consequences that don't reverse easily. Muscle tissue is metabolically active; losing it reduces the body's baseline energy demand and makes future weight management harder. After a certain age, rebuilding lost muscle requires sustained, deliberate effort, and even then the results are limited. The weight that returns after stopping the drug is fat. The muscle that left during treatment doesn't come back automatically.

This is the part of the GLP-1 story that receives the least attention. The drugs are being evaluated primarily on total weight lost. The question of what was lost, and what the body looks like on the other side, is a different calculation.

What's actually missing

Our position isn't that these drugs should never be used. It's that they're being deployed without the infrastructure that made them work in the trials, and without serious preparation for what happens when they stop. The wrap-around support, the dietary coaching, the behaviour change programme: those ended when the prescription ended. For most people, that's within a year.

The deeper issue is that 70% of people coming off these medications were never given a functioning alternative. Diet culture failed them for decades, which is how a weekly injection became the most compelling option on the table. What was missing wasn't willpower or discipline; it was a way to understand what their metabolism was actually doing, and practical tools to work with it rather than against it.

Data-led habit change is harder to sell than a weekly injection. It requires engagement, not just compliance. But it produces something the drug doesn't: a body that has actually learned to regulate itself, rather than one that was regulated temporarily from the outside.

The question worth sitting with is what happens after the drug stops, and whether anyone involved in prescribing it has a real answer.