Your GLP-1 Protein Floor, Calculated — And Then Actually Tracked

🧮 Use the interactive version: open the calculator → — enter your details and get your number in seconds.

Most people losing weight on a GLP-1 should aim for a daily protein floor of about 1.2–1.6 g per kg of body weight — higher than the roughly 0.75 g/kg general baseline — to protect lean muscle while appetite is suppressed. For a 70 kg (154 lb) adult that's about 84–112 g per day, split into 20–40 g across 3–4 meals. Enter your details in the calculator above to get your number, then track it as a daily floor. This is information, not medical advice — confirm targets with your prescriber.

How much protein you need on a GLP-1 (the number, by goal)

The short version: if you're actively losing weight on semaglutide (Ozempic, Wegovy) or tirzepatide (Zepbound, Mounjaro), aim for roughly 1.2–1.6 g of protein per kg of body weight per day. That's noticeably above the ~0.75 g/kg the NHS and British Dietetic Association cite as a general-population reference — and that gap is the whole point. General baselines assume you're eating enough overall. On a GLP-1, you often aren't.

Here's the mindset shift that matters most. On these medications, calories are the wrong thing to fixate on. Appetite drops, portions shrink, and for most people a calorie deficit shows up on its own — that's the drug working. So protein stops being a number to stay under and becomes a number to clear. Think of it as a floor, not a budget.

The 1.2–1.6 g/kg range sits comfortably inside what obesity-medicine and sports-nutrition consensus recommend for adults losing weight. The International Society of Sports Nutrition (ISSN) position stand on protein supports higher intakes during energy restriction to preserve lean mass. Your exact target depends on your goal and how much resistance training you do — which is why the calculator asks.

Want the number to become a habit instead of a screenshot? You can track your protein floor meal-by-meal in Tiro, with a running bar that shows grams-to-go in real time.

Why a protein floor beats a calorie budget when appetite crashes

GLP-1 medications slow gastric emptying and quiet the appetite signals a lot of people call "food noise." That's exactly what makes them effective — and exactly what makes protein hard. When total intake falls and you're in a calorie deficit, your body can pull from muscle as well as fat unless protein stays high enough to defend it.

This isn't a small footnote. Body-composition sub-analyses of the major GLP-1 weight-loss trials — including the semaglutide STEP program (published in The New England Journal of Medicine, 2021) and the tirzepatide SURMOUNT-1 trial — have reported that a substantial share of the weight lost is lean mass. Across these studies the lean-mass fraction, in some analyses, has run roughly a quarter to a third of total weight lost. The direction of the finding is well established even where the exact figure varies by study and measurement method.

That's the case for a floor. A calorie ceiling shrinks as your appetite shrinks — it gets easier to stay under it every week, which sounds like success but can quietly cost you muscle. A protein floor does the opposite: it holds the line regardless of how little you feel like eating. Resistance training on top of adequate protein is the best-supported combination for holding onto lean mass during weight loss.

And because the scale can't tell muscle loss from fat loss, weight alone is a blunt instrument here. You can watch lean mass with a 3D body scan, not just the scale — measurements and body-fat percentage catch what the number on the floor misses.

Reconciling the ranges: 0.75 vs 1.2–1.6 vs 1.6–2.2 g/kg

If you've searched semaglutide protein requirements, you've probably hit three different numbers and no explanation. Here's how they fit together — they're answering different questions.

The ~0.75 g/kg figure is a population reference intake, not a weight-loss target — it's the amount to prevent deficiency in a healthy adult who's eating enough. During active weight loss, evidence points higher, to protect muscle in a deficit. Add regular strength training and the ceiling rises again. Older adults trend toward the top of each band because of anabolic resistance — muscle gets less efficient at using protein with age.

One methodology note the naive calculators miss: adjusted body weight. If you're at a higher BMI, multiplying your full body weight by a g/kg figure overshoots, because fat mass doesn't have the same protein demand as lean mass. Clinical calculators — several of the ranking GLP-1 tools included — use an adjusted body weight formula so the target reflects the tissue that actually needs protein. This calculator applies the same approach, which is why its number can look lower (and more realistic) than a quick weight × 1.6 on the back of a napkin.

Grams of protein per meal on a GLP-1 (the per-meal split)

Your daily floor only works if you can actually distribute it. The common guidance — echoed in the ISSN position stand — is roughly 20–40 g of protein per meal, which is the range associated with maximally stimulating muscle protein synthesis (MPS) in a single sitting. For most adults, ~30 g per meal does the job; older adults tend toward 30–40 g to overcome that anabolic resistance.

The practical move is to spread protein across 3–4 meals rather than loading it into one big dinner. Four meals at ~28 g each gets a 70 kg adult to ~112 g without any single plate feeling enormous — which matters a lot when early satiety means you may not finish what's in front of you.

Which is the other rule of GLP-1 eating: protein first. If you fill up after a few bites, the bites you take should be the ones that count. Lead with the chicken, eggs, fish, Greek yogurt, tofu or shake before the carbs and sides. You're not trying to eat more — you're trying to make the little you eat protein-dense.

This is the piece Tiro is built around. Instead of a static "112 g/day," you see your protein floor as a running per-meal bar — grams logged, grams to go, per meal — so the target is a live number, not a calculation you did once and forgot.

What to do when you physically can't hit your protein floor

Some weeks you won't — and that's usually about side effects, not willpower. Nausea is the most common gastrointestinal side effect of GLP-1 medications, and it typically eases once you settle on a stable dose. Titration — stepping the dose up gradually — is the main tolerability lever, which is precisely why prescribers escalate slowly. The FDA prescribing information for Wegovy (semaglutide) lays out the standard step-up schedule and lists GI effects like nausea, vomiting and diarrhea as the most frequent.

When the floor feels out of reach, a few practical rescues help:

• Go liquid and soft. Protein shakes, Greek yogurt, cottage cheese, eggs, soups with added protein — easier to get down than a dense steak when your stomach is unhappy.
• Smaller, more frequent meals. Five small protein hits beat two big ones you can't face.
• Protein first, every time. Non-negotiable when appetite is low.
• Time meals to your best-appetite window. For many people that's a certain point in the weekly injection cycle — eat your biggest protein meals when you feel most able to.

Do not change your dose to manage this on your own. If nausea, vomiting or an inability to eat is persistent or severe, that's a conversation for your prescriber or GP — dosing decisions are theirs to make. Inside Tiro you can log the side effect and get mitigation tips, plus hydration and fiber nudges, and track whether symptoms line up with a dose change — useful context to bring to that appointment.

UK note: protein on Mounjaro

In the UK, Mounjaro (tirzepatide) is now the dominant weight-loss brand — Zepbound isn't sold here, so Mounjaro is the tirzepatide you'll be prescribed, whether through the NHS or a private clinic. Wegovy and compounded semaglutide are also in use.

The protein logic is identical to the US picture, just measured in kg from the start. The NHS and British Dietetic Association reference a general intake of around 0.75 g/kg for a healthy adult — but that's a baseline, not an on-treatment target. During active weight loss on Mounjaro, the same 1.2–1.6 g/kg applies to help protect lean mass, and the calculator above defaults to kilograms. As always, if you're under NHS or private specialist care, your clinician's guidance takes precedence over any calculator.

How to track your protein floor (not just calculate it)

A calculated number is a good start and a bad finish. Every other GLP-1 protein calculator hands you a figure and stops — you screenshot "112 g" and then wing it at dinner.

Tiro closes that loop. Set your calculated floor in the Tiro app, and it becomes a tracked daily target: a running gram total, the per-meal split laid out for you, and a bar that fills as you log. Because your dose won't stay still, the floor holds even as you titrate — you can keep your floor steady as your dose titrates instead of watching your intake quietly collapse when appetite drops. Protein-first, floor-first, on autopilot.

FAQ

How much protein should I eat per day on Ozempic or Wegovy? About 1.2–1.6 g per kg of body weight during active weight loss — roughly 84–112 g for a 70 kg adult, versus the ~0.75 g/kg general baseline. Use the calculator for your number and confirm it with your prescriber or dietitian.

How many grams of protein per meal on a GLP-1 — is 30 g enough? Yes for most adults. Around 20–40 g per meal hits the muscle protein synthesis threshold; 30 g is plenty for most people, 30–40 g for older adults. Spread it across 3–4 meals.

Should I count protein or calories on a GLP-1? Count protein as a floor to hit. Appetite suppression usually creates the calorie deficit for you, so the real risk is under-eating protein, not overeating calories.

How much protein on Mounjaro in the UK? The same ~1.2–1.6 g/kg on-treatment target during weight loss, against the roughly 0.75 g/kg NHS/BDA baseline. The calculator supports kg by default.

What if I can't eat enough protein because of nausea? Use shakes and soft proteins, smaller frequent meals, and protein-first eating. Nausea often eases on a stable dose — raise persistent symptoms with your prescriber rather than adjusting your dose yourself.

Does protein really protect muscle on GLP-1 medications? Body-composition data from GLP-1 trials show a meaningful share of lost weight can be lean mass. Higher protein plus resistance training is the best-supported way to preserve it.

Sources

• FDA Prescribing Information — Wegovy (semaglutide) injection, U.S. Food & Drug Administration
• FDA Prescribing Information — Zepbound and Mounjaro (tirzepatide), U.S. Food & Drug Administration
• STEP 1 trial, body-composition data — New England Journal of Medicine, 2021
• SURMOUNT-1 trial (tirzepatide) — New England Journal of Medicine / body-composition sub-analysis
• International Society of Sports Nutrition (ISSN) Position Stand: Protein and Exercise — Journal of the International Society of Sports Nutrition
• NHS — Eat well / protein guidance, National Health Service (UK)
• British Dietetic Association (BDA) — protein reference intakes
• NICE — guidance on weight-management medications (UK)

Calculator output is an estimate for information only, not a medical prescription. This article is for information only and is not medical advice. Protein targets are estimates — talk to your prescriber or a registered dietitian before changing your diet or medication.