Protein target on a GLP-1
Work out how much protein you need each day to hold on to muscle while you lose weight on a GLP-1, plus the per-meal split that actually drives it.
Read this first. This is a general population estimate, not a personalised nutrition plan. If you have kidney disease, liver disease, or any condition that restricts protein, do not use this number. Ask your clinician or a registered dietitian for a target built around your labs.
Pick what you actually do now, not what you plan to do. Resistance training is the part that matters most here.
A calorie deficit is when lean mass is most at risk, so the target goes up.
Spreading protein evenly beats stacking it into dinner.
Your per-meal split
Muscle protein synthesis responds to each individual meal, so an even split does more for lean mass than the same total dumped into one sitting.
| Meal | Protein target |
|---|
Why protein is the whole ballgame on a GLP-1
Every method of losing weight costs you some lean mass. That is normal physiology, not a drug side effect. In the STEP 1 body composition substudy, roughly 40% of the weight lost on semaglutide was lean mass, and the proportion of lean mass in the body actually went up because fat came off faster. The problem is not the ratio. The problem is the pace and the appetite.
GLP-1 medication does two things at once. It cuts your appetite hard, and it slows gastric emptying so you feel full on a small volume of food. That combination makes it easy to run a very large deficit without noticing, and protein is usually the first thing to fall out of the diet because it is the most filling macronutrient and the least appealing when you are already full. People end up eating 40 or 50 grams a day without realising it.
Lean mass is not a vanity metric. It is most of your resting metabolic rate, your insulin sensitivity, your grip strength, and the thing that determines how your body handles a fall at 70. Lose it and your maintenance calories fall with it, which is exactly the setup for regain when you come off the medication.
How this calculator works
Baseline by activity. The target starts at 1.2 g per kg of body weight for sedentary adults and rises to 1.6 g per kg for people training hard. That range is well above the 0.8 g per kg RDA, which is a floor set to prevent deficiency, not a target for someone deliberately losing weight.
A step up while losing. Being in an active calorie deficit adds 0.4 g per kg, which puts you in the 1.6 to 2.0 g per kg band that the protein and body composition literature supports for preserving lean mass during weight loss.
An age adjustment. Over 60, muscle becomes less responsive to a given dose of protein. This is called anabolic resistance, and it means older adults need more protein per meal to trigger the same muscle protein synthesis response. The calculator adds 0.1 g per kg above 60.
A per-meal split. The total is divided evenly across your meals, because the synthesis response is per meal rather than cumulative. Below roughly 25 to 30 grams in a sitting, the response is weak in most adults, and higher in older adults.
The result is capped at 2.2 g per kg. Beyond that there is no additional benefit for muscle preservation in healthy adults, and the extra just displaces food you need for other reasons.
Hitting the number when you are not hungry
The target is easy. Eating it on a drug that removes your appetite is not. What actually works:
Protein first, every single meal. Eat the protein on the plate before anything else. On a GLP-1 you will often stop eating halfway through, and whatever you left is whatever you ate last.
Drink it when you cannot chew it. Liquid protein bypasses most of the fullness problem. A shake, a high-protein yoghurt drink, or milk-based coffee all land when solid food will not.
Front-load the day. Appetite on injection day is usually worst in the evening. Breakfast is often the meal you can still get down, so make it the biggest protein hit rather than the smallest.
Density over volume. Swap to versions of the same food with more protein per bite: Greek yoghurt instead of regular, cottage cheese instead of cream cheese, higher protein pasta, skimmed milk powder stirred into things.
What 30 grams of protein actually looks like
| Food | Protein |
|---|---|
| 100 g cooked chicken breast | About 31 g |
| 150 g cooked salmon | About 38 g |
| 1 scoop whey protein powder | About 25 g |
| 1 cup plain Greek yoghurt | About 22 g |
| 1 cup cottage cheese | About 25 g |
| 3 large eggs | About 19 g |
| 150 g firm tofu | About 17 g |
| 1 cup cooked lentils | About 18 g |
Protein alone is not enough
Protein gives your body the material to keep muscle. Resistance training gives it the reason. Without a stimulus, extra protein is largely wasted on lean mass preservation. Two or three sessions a week of anything progressive counts: free weights, machines, bands, bodyweight. This is the single highest-leverage habit to add while you are on the medication, and it is far easier to keep muscle now than to rebuild it later.
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