By Trainer Dan · 2025-01-20
Why cardio alone is the wrong tool while you're on Ozempic or Mounjaro — and the simple 3-day strength template that protects your muscle, energy and metabolism while the weight comes off.
If you take one thing from this article, take this: on GLP-1s, cardio doesn't save you — strength training does.
I see the same mistake every week in my gym. Someone starts Ozempic, Wegovy or Mounjaro, gets excited about the weight loss, and decides to "match it" with hours of treadmill, spin or step counts. Six months later they've lost 20 kg, but they're tired, weak, the scale has stalled, and they look softer than when they started. The fat went, sure. So did a chunk of their muscle.
Here's the fix.
When you eat less (and you will), your body picks where the weight comes off. By default, it'll happily take it from muscle as well as fat. Strength training is the signal that tells your body, "no — keep this, I'm using it." Without that signal, the muscle goes.
Lifting weights on a GLP-1 does three big things:
1. Protects lean mass so your weight loss is mostly fat 2. Keeps your metabolism up — muscle burns calories at rest 3. Builds the shape that the scale doesn't measure (the "looking good in clothes" part)
Cardio is fine. Walk every day, your heart will thank you. But cardio is the side dish on a GLP-1. Lifting is the main.
You don't need a fancy program. You need three sessions a week, around 45–60 minutes each, hitting your whole body with compound lifts — exercises that work multiple muscles at once.
Rest 90 seconds between sets. Use a weight that makes the last 1–2 reps genuinely hard but never breaks your form. That's the whole game.
GLP-1s rob your appetite, which means some days you'll roll into the gym running on fumes. Don't skip — scale. Use my 50% rule:
- Cut the weight to 50% of what you'd normally lift - Cut the sets to 2 instead of 3 - Keep the exercises the same
A short, light session still tells your muscles "we're still using you." That's all you need on a hard day. Save the personal records for the weeks you're eating well.
You should still move every day — just stop using cardio to "burn off" food.
- Walk 7,000–10,000 steps a day. Easy, low impact, doesn't crush your appetite further. Best single thing you can do outside the gym. - One optional 20-minute conditioning session per week. Bike intervals, rower, hill walk. That's it.
Hours of steady-state cardio while in a deep calorie deficit is how people end up exhausted, hangry and stalled. Don't be that person.
I'll keep saying it because it's true: lifting without enough protein is a waste of effort, and protein without lifting is half a strategy. Together they're the difference between losing 20 kg and looking smaller-but-soft, versus losing 20 kg and looking like an athlete.
Hit your 1.6–2.2 g/kg of protein. Train three times a week. Walk daily. Sleep 7+ hours. Let the medication do the appetite part.
Do that for 6 months and you'll come off the other side of this leaner, stronger, and — this is the bit nobody tells you — far more likely to keep the weight off when the medication eventually tapers down. Muscle is metabolic insurance. Build it now.
See you in the gym. — Dan