Guide
Your first month on Mounjaro: how much protein, and how to hit it
In your first month on Mounjaro, set your protein target at 1.2 to 1.6 g per kg of your goal weight (0.55 to 0.7 g per lb), for most people 90 to 130 g a day, and eat it before anything else at each meal. The habits you build in these first weeks are the ones that survive the steps above them.
Your number, before anything else
Protein is what decides whether the weight you lose is fat or muscle. Work your number out once and we will keep it with you on every page here. No account, no email.
Saved in this browser only. Your dose and how you feel on Mounjaro stay between you and your prescriber.
Four things to set up in week one
Many people notice Mounjaro on the very first step more than they expected, with appetite dropping within days. If that is you, the protein-by-the-clock approach starts now rather than after the first dose step.
Work out your number from goal weight
Not current weight. If you weigh 95 kg (209 lb) and your goal is 75 kg (165 lb), the floor is 75 x 1.2 = 90 g a day, and 120 g is a good target. The calculator does it in ten seconds, in kilos or pounds.
Weigh food for one week only
A cheap kitchen scale and one week of weighing shows you what 120 g (4 oz) of chicken looks like. After that you can eyeball it. Most people find their 'good' days were 60 to 70 g. Stock the fridge with what you will eat on a bad day: yoghurt, eggs, tinned fish, cottage cheese.
Take your three baseline numbers this Sunday
Strength test, protein average, upper arm tape. Without a week-one baseline you will not know in week eight whether the arm has shrunk.
Expect it to start early
Mounjaro blunts appetite for many people from the first step, sometimes within the first few injections. If your first week's log shows under 80 g of protein, move to protein-by-the-clock immediately.
What month one looks like on Mounjaro
Mounjaro is usually started low and stepped up at intervals of several weeks, on a schedule your prescriber sets. The first weeks are usually the mildest, and that is the trap: appetite is a little lower, the scale moves, and nothing seems to need managing. Tirzepatide is the medication where people most often describe a very short appetite window: a few bites, then done. It is not that food is unappealing; it is that the door closes fast. Whatever goes through it first is what you get.
Pooled across 20 randomised trials, 25.4% of the weight lost on tirzepatide was lean mass, against 26.2% when the same weight came off by diet alone, and 17.5% when resistance training was added. The muscle you lose in the first three months is the hardest to get back. The month-one job is not to lose weight faster; it is to set the protein floor before the appetite falls through it.
A 120 g protein day for month one
- Breakfast: 2 eggs plus 150 g (5 oz) Greek yoghurt: about 27 g
- Lunch: 120 g (4 oz) cooked chicken in a wrap or on salad: about 35 g
- Afternoon: 250 ml (8.5 fl oz) milk with a scoop of protein powder: about 30 g
- Dinner: 150 g (5 oz) fish or lean mince with vegetables: about 32 g
About 124 g total. Move dinner earlier if evening appetite is lowest, which on Mounjaro it often is.
Work out your own target on MounjaroThree numbers, every Sunday
Log these in week one; week eight needs a baseline.
One strength test, same way every week
Goblet squat reps at a fixed weight, push-ups, or the 30-second sit-to-stand for beginners. Fat loss does not make you weaker, so a number that drops three or four weeks running is a real signal, and it is fixable. It measures what you can do, not how much muscle you have.
Average protein a day, whole week
Not your best day. 1.2 to 1.6 g per kg of goal body weight (0.55 to 0.7 g per lb), floor 1.2, protein first at every meal.
Upper arm tape, same spot, relaxed
Centimetres or inches. The waist shrinks whatever you do; if the arm shrinks as fast, that is muscle. Weight is number four, same day and time. The scale tells you what you lost. These tell you what you kept.
What belongs with your prescriber, not with us
- Nausea or vomiting that stops you keeping food down for more than a day
- Severe stomach pain, especially if it goes through to your back
- Any question about when or whether to move to the next dose step. That is your prescriber's call, not yours and not ours
Dose and timing on Mounjaro are your prescriber's decisions; we coach the food and the strength.
Questions people ask
How much protein should we eat in our first month on Mounjaro?
1.2 to 1.6 g per kg of goal body weight (0.55 to 0.7 g per lb). For a 70 kg (154 lb) goal that is 84 to 112 g a day. Start at the floor and build.
Do we need protein powder on Mounjaro?
No, but it is the easiest 25 to 30 g you will get on a day when food does not appeal. A tool for the low days, not a replacement for meals.
Does the first month on Mounjaro do anything?
The first step is there to let your gut adjust, but plenty of people notice appetite drop on it. Treat it as real: set the protein floor and the baseline numbers in week one.
Where these numbers come from
Three figures set your first month: the daily floor, the per-meal share and the amount of one amino acid that has to be in each sitting.
Guideline-informed protein targets during this kind of weight loss start at 1.2 g per kg of body weight a day (0.55 g per lb). Arslan S, Clinical Nutrition ESPEN 2026
Spread across meals at roughly 0.3 to 0.4 g per kg per meal, rather than taken mostly at dinner. Arslan S, Clinical Nutrition ESPEN 2026
Each of those meals wants roughly 2.5 to 3 g of leucine, the amino acid that actually switches muscle building on. That is about 30 g of whey, 120 g of chicken breast, or four eggs. Arslan S, Clinical Nutrition ESPEN 2026
The papers these numbers come from
- Arslan S. Medical nutrition in the glucagon-like peptide-1 (GLP-1) era: Protein strategies, micronutrient monitoring, and lean mass preservation. Clinical Nutrition ESPEN, 2026. Narrative review, guideline-informed targets. doi:10.1016/j.clnesp.2026.103305
- Eisa N, Barood O. Lean Mass Changes With Incretin Therapy Versus Lifestyle Intervention: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Diabetes, Obesity and Metabolism, 2026. 20 randomised controlled trials, 15,782 participants. doi:10.1111/dom.70666
Last reviewed 18 September 2026. We update these figures when a larger or better study replaces them, and we say what changed. How we handle evidence.
The Keep Muscle Kit
The whole system for Mounjaro, in five PDFs
The workbook, Sunday numbers tracker, 2-day strength plan, injection-day card, and meal plans at 100, 120 and 140 g protein. Instant download.
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EverStrong provides nutrition and strength coaching and education. It is not medical advice and does not replace your prescribing doctor. Consult your doctor before starting a new exercise or nutrition plan, especially with a heart, kidney, liver or metabolic condition, if pregnant, or with a history of disordered eating.