What should I do before starting a GLP-1 medication?
Use the window while you can still eat normally. Work out a protein target and find out what you currently eat against it, start resistance training before energy drops, learn a few protein-dense foods you actually like, and take a baseline measurement that is not only your weight.
Key takeaways
- The weeks before the first dose are the only ones where building an eating habit is easy. Use them.
- Find out what you currently eat before appetite changes, so you have a baseline rather than a guess.
- Start resistance training now, while energy is normal, rather than trying to begin it during the steepest loss.
- Take a measurement that is not weight: a tape measure at the waist, or what you can lift.
- Everything clinical, including whether the medication is right for you, sits with your prescriber.
There is a window here that is easy to miss. Before the first dose, you can still eat normally, you have normal energy, and nothing is urgent. Every habit worth having later is cheaper to build now.
- A protein target worked out from your body weight, and a week of honest logging against it.
- Two or three resistance sessions a week, started now rather than later.
- Three or four protein-dense foods you actually like and will reach for without deciding.
- A baseline that is not only your weight: a waist measurement, and a note of what you can lift or carry.
Find out what you eat now
Most people do not know. Protein is concentrated in a few foods and easy to undercount, and the estimate people carry around is usually optimistic.
The value of doing this before the first dose is that afterwards you cannot. Once appetite is suppressed, the ordinary feedback between how much you ate and how full you feel comes apart, so a day that feels like plenty may be well short. A baseline taken now is the only version of that number you will get from a normal week.
A week is enough. How the target is derived has the arithmetic, and the calculator does it from your weight and situation.
Start the training first
This is the recommendation with the largest gap between how obvious it is and how rarely it happens.
Resistance training is the half of muscle preservation that is not food, and starting it during a steep calorie deficit with no appetite is considerably harder than starting it now. A few weeks of learning the movements at normal energy means that later you are maintaining something rather than beginning it.
Two or three sessions a week loading the major muscle groups. It does not have to be a gym.
There is also a finding worth knowing: in the protein supplementation meta-analysis, the effect on fat-free mass was larger in people already resistance-trained.3 Arriving already training is not just easier, it appears to work better.
Pick the foods now
When appetite drops, decisions get harder, not easier. Somebody with three familiar protein-dense foods in the fridge eats one of them. Somebody choosing from scratch on a bad day eats toast.
Worth having settled in advance:
- One cold thing that needs no preparation: Greek yoghurt, skyr, cottage cheese.
- One that keeps: tinned fish, eggs.
- One drink, if you think you will need it. Whether a shake earns its place is worth reading before buying a large tub of something you have never tasted.
Buy small quantities and find out which ones you actually like now, while food still appeals.
Measure something other than weight
Roughly a quarter of the weight lost on these medications is lean mass, in placebo groups as well as on the drug.1 The whole point of the protein and the training is to move that ratio, and a bathroom scale cannot tell you whether you did: it reports two tissues as one number.
Two free baselines, five minutes:
- A tape measure at the waist, noted with the date.
- What you can lift or carry, however informal. Even "I can do six press-ups" is a data point you will be glad of in six months.
If your loss goes well, these are what will show it. If it does not, these are what will tell you early enough to change something.
What is not on this list
Anything clinical. Whether the medication is appropriate for you, which one, at what dose, what to expect, and how to handle its effects are all decisions for the clinician prescribing it. This page is general reference material about protein and muscle, and it does not know your history.
Bring the questions you have to that appointment. Prescribers expect them, and it is a better use of the visit than the eating questions, which you can settle from a page like this one.
More questions about GLP-1
Should I change my diet before starting?
Not dramatically. The useful preparation is finding out what you currently eat and identifying a few protein-dense foods you genuinely like, so that when appetite drops you are reaching for something familiar rather than making decisions. A large diet overhaul before starting mostly gives you two adjustments at once.
Is it worth starting the gym before or after?
Before, clearly. Beginning resistance training while energy is normal is far easier than beginning it during a steep deficit with a suppressed appetite. A few weeks of getting used to the movements means you are maintaining a habit later rather than starting one.
What baseline measurement should I take?
Weight, but not only weight, because it reports fat and muscle as one number. A tape measure at the waist and a note of what you can lift or carry give you a way to tell later whether the composition went well. Those two are free and take five minutes.
References
- Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight
- Self-monitoring in weight loss: a systematic review of the literature
- A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults
