You're on a GLP-1 medication. You're barely eating. The scale hasn't moved in weeks — or it's gone back up. If eating less was the answer, the medication would have worked by now.
Here's what's actually happening.
Your appetite is down, but so is your nutrition
GLP-1 medications like Ozempic and Mounjaro are effective at reducing appetite. But appetite suppression without nutritional structure creates a new problem: you eat less of everything, including protein, essential fats, and the micronutrients your metabolism depends on.
The result? Your body starts conserving energy rather than burning fat.
You're losing muscle, not just fat
Studies on GLP-1 medications consistently show that up to 30–40% of the weight lost can be lean muscle mass. Muscle is metabolically active tissue — it's what keeps your metabolism running. Lose too much of it and your body burns fewer calories at rest, making further fat loss harder even on low food intake.
This is the cycle most women on GLP-1s don't know they're in: less food → less protein → muscle loss → slower metabolism → weight stalls → eat even less → more muscle loss.
Your thyroid may be underperforming
Chronic calorie restriction — which is effectively what happens when a GLP-1 kills your appetite — can slow the conversion of T4 (inactive thyroid hormone) to T3 (the active form). T3 drives your metabolic rate. When it drops, fat loss slows regardless of how little you eat.
If you've been on a GLP-1 for months and feel cold, tired, and sluggish, this is worth investigating with a full thyroid panel (not just TSH).
Cortisol is working against you
Under-eating is a physiological stressor. When your body perceives sustained energy deficit, cortisol rises. Elevated cortisol promotes fat storage — particularly around the midsection — and breaks down muscle tissue for fuel. For women in perimenopause, cortisol is already elevated, and the combined stress of hormonal change plus calorie restriction can create a perfect storm for weight-loss resistance.
What actually works
The answer isn't eating less. It's eating strategically:
Prioritise protein — aim for 1.6–2.0g per kilogram of body weight daily to protect muscle mass
Structure your meals — even if you're not hungry, your body needs consistent fuel to maintain metabolic function
Get a full blood panel — thyroid (T3, T4, TSH), iron, B12 and vitamin D at minimum
Add resistance training — the single most effective way to preserve and rebuild muscle on a GLP-1
Work with a nutritionist who understands GLP-1s — not all practitioners have experience with these medications
Ready to get your GLP-1 working properly?
I work with women on GLP-1 medications to protect muscle, fix nutrition structure, and get their metabolism responding again. If you're stuck, a single consultation can identify exactly what's going on and give you a clear plan forward.
The importance of
strength training
and high protein
diet on a GLP 1