Do I have to lift weights while on a GLP-1?

Muscle is expensive tissue to maintain, and a body in an energy deficit will shed anything it is not being asked to use. Resistance training is the request. It is the reason two people can lose the same 20 kg and end up with visibly different bodies and different function.

What the current guidance says

The 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society recommends strength training at least three times a week, plus at least 150 minutes a week of aerobic activity, alongside a protein intake of 1.2 to 1.6 g/kg per day, for anyone losing weight on GLP-1 therapy. Those three elements work together. Protein without the training stimulus and training without the protein both underperform.

What actually counts as resistance training

It means loading a muscle against resistance until it is genuinely challenged, then progressively increasing that load. Free weights, machines, resistance bands and bodyweight work all qualify. Six to eight exercises covering legs, hips, back, chest, shoulders and trunk, two or three sets each, twice or three times a week, is a sufficient programme for most people. Walking is valuable for cardiovascular health, glucose control and mood, and it does not preserve muscle. Neither does yoga alone, in most formats.

How to start if you have never trained

Begin before you escalate to a higher dose, not after, because the first months carry the fastest weight loss. Start with movements you can perform with control: a sit to stand from a chair, a hip hinge, a row, a press, a carry. Two sessions of 25 minutes a week performed consistently for six months beats a five day plan that stops in week three. Expect strength to rise at first even while weight falls, because early gains are largely neurological. If you have joint disease, cardiac disease or are over 65, ask for a programme designed around those constraints rather than skipping the training.

Book the sessions into your week the way you book the injection. Track one lift and one function marker, such as how many chair stands you can do in 30 seconds, and recheck them every three months. If the scale is falling and those numbers are falling with it, the plan needs changing before you lose more weight.