How to get ready for GLP 1, the prep that protects your muscle
By Jimmy, founder of 120to90. Medically cautious, not medical advice. See the disclaimer below. Last updated June 2026.
The week before your first dose matters more than most people realise. A GLP 1 will quietly turn your appetite down. That is the point. But if you walk in with no plan, the medication makes the decisions for you, and the result is often weight lost fast with too much muscle going with it. For a man over 45, that is the trap. Get ready properly and you tilt the whole thing toward fat loss with your strength held.
I am Jimmy. I am 48, on my own road from 120kg toward 90, losing weight under my doctor on a GLP 1. Here is exactly how I would prepare if I were starting again, the mental side and the physical side, in plain language.
Why preparation changes the result
The medication is one lever. What you eat, how you train and how you track are the other three, and they decide whether the weight you lose is fat or muscle. Body composition studies of these drugs show a real share of rapid weight loss can be lean tissue. Preparation is how you protect against that before the appetite drop ever hits. The men who get ready first do not just feel better in week one, they keep more of their muscle through the whole journey.
Get your head right first
Decide what success looks like, in advance. Not a number on the scale. A waist that shrinks, strength that holds or climbs, and energy that stays. Write it down before you start, because once the scale starts dropping it is easy to chase the wrong target.
Expect the appetite drop, and plan for it. You will not feel like eating much. That is normal and it is the medication working. The risk is undereating protein, which is the one thing you must not skimp on. Knowing this in advance is half the battle.
Accept slow. Faster is not better. Half a kilogram to one kilogram a week keeps more muscle than a crash. Going in with that expectation stops you panicking when the scale moves gently.
Build the physical habits before day one
This is the part almost nobody does, and it is the difference maker. Start these in the week or two before your first dose, while your appetite is still normal and habits are easy to build.
Start lifting now
Two to four short resistance sessions a week is the signal that tells your body to keep its muscle while it burns fat. You do not need a gym. Kettlebells, a pair of dumbbells and a bench cover it. Beginning before the medication means the habit is already in place when your energy dips.
Dial in your protein
Most evidence points to roughly 1.2 to 1.6 grams of protein per kilogram of body weight per day during weight loss, and the higher end matters more as we age. Practise hitting it now, while eating is easy, so it is automatic later. Think eggs, chicken, fish, Greek yoghurt, lean mince and a simple whey shake.
Sort your kitchen
Stock the high protein staples and clear out the food you will regret buying once cravings are gone. A prepared kitchen makes the right choice the easy choice.
Get your water habit going
Good hydration helps with the nausea and tiredness that can come in the early weeks. Start before, not after.
Set up the practical side
Write your questions for the doctor. Dose and how it steps up, what side effects to expect, what to do about nausea, how it interacts with anything else you take, and what the plan is if it stops working. Walk in with the list.
Plan for the first week. Mild nausea, fullness and tiredness are common early on. Smaller meals, plenty of water and steady protein help. If anything feels wrong or severe, call your doctor, that is what they are there for.
Set up your tracking. Pick how you will log your weight, your waist and your strength in one place from day one. A starting baseline is the only way to know later whether you kept your muscle. The 120to90 app is built to do exactly this.
Your GLP 1 prep checklist
- Defined what success means beyond the scale
- Started two to four short resistance sessions a week
- Practised hitting your daily protein target
- Stocked the kitchen with high protein staples
- Built a steady water habit
- Wrote your questions for the doctor
- Set up weight, waist and strength tracking with a baseline
Tick those off before your first dose and you are not just starting a medication, you are starting a plan. If you want all of it done for you, the kettlebell workout, the high protein eating plan and the tracking, that is what the free plan is for. For the full method, read our guide to keeping muscle on GLP 1. And to see what the result looks like, read our real GLP 1 success stories.
Frequently asked questions
What should I do before starting a GLP 1?
Build the muscle protecting habits first. Start resistance training, practise hitting your protein target, stock your kitchen, build a water habit, write your questions for the doctor and set up a way to track weight, waist and strength from day one.
What should I eat when starting a GLP 1?
Lead with protein at every meal, around 1.2 to 1.6 grams per kilogram of body weight per day, since appetite drops and muscle needs protecting. Keep meals smaller and steady, and drink plenty of water to ease early nausea.
How do I avoid losing muscle on a GLP 1?
Lift weights two to four times a week, eat enough protein and lose weight slowly. Those three together push the loss toward fat and protect the muscle underneath.
Will I feel sick when I start?
Mild nausea, fullness and tiredness are common in the early weeks as your body adjusts. Smaller meals, hydration and steady protein help. Anything severe or worrying is a call to your doctor.
Disclaimer. I share what I have learned on my own journey and I am not a doctor. GLP 1 medications are prescription drugs with real risks and side effects. If you have a health condition, take any medication, or are starting a new diet or training plan, speak to your own doctor first.