Muscle Preservation Calculator
Losing weight too fast or without enough protein costs you muscle, not just fat. Enter your details to get your protein target, a muscle-loss risk check, and a simple plan to hold onto the muscle you have.
Muscle Preservation Calculator
Losing weight too fast or without enough protein costs you muscle, not just fat. Enter your details to get your protein target, a muscle-loss risk check, and a simple plan to hold onto the muscle you have.
Educational only, not medical advice. This tool gives general nutrition guidance and says nothing about any medication, dose, or timing. If you’re on a weight-loss program or medication, follow your prescriber’s and dietitian’s guidance — do not change your treatment based on this tool.
Your details
Protein target 136 grams per day. Muscle-loss risk: Higher.
Muscle-loss risk
HigherA general guide, not a precise measurement — driven by your loss rate, protein, and training.
- WatchLoss rateA moderate pace (0.82%/week) — fine with enough protein and training.
- RiskProtein intakeWell below the 136 g/day needed to hold muscle in a deficit.
- WatchResistance training1–2 days/week helps — 2–3 is the sweet spot.
Your muscle-saving checklist
- Add about 46 g of protein a day to reach 136 g (about 1.6 g/kg).
- Do resistance training 2–3 times a week — even bodyweight or bands count.
- Keep your loss around or below 1% of body weight per week.
- Spread protein across 3–4 meals and prioritize whole-food sources.
Dial it in: Protein Intake Calculator · Macro Calculator
Educational only, not medical advice. This tool gives general nutrition guidance and says nothing about any medication, dose, or timing. If you're on a weight-loss program or medication, follow your prescriber's and dietitian's guidance — do not change your treatment based on this tool.
This is an educational estimate, not medical advice. Consult a qualified professional.
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The three levers that keep muscle
When you lose weight, some of what you drop can be muscle rather than fat. How much depends almost entirely on three things you control:
- Protein — enough to signal your body to keep muscle (far more than the basic RDA).
- Resistance training — the strongest signal of all that your muscle is still needed.
- Pace — losing too fast tips the balance toward muscle loss.
How much protein to keep muscle in a deficit
Protein needs go up, not down, when you’re cutting calories. The research supports roughly 1.6–2.4 g of protein per kg of body weight per day to preserve (or even build) muscle while losing fat — toward the higher end if you’re losing quickly or you’re older, since both make muscle harder to hold. A controlled trial found that a higher-protein group training in a steep deficit actually gained a little lean mass while losing fat, where a lower-protein group did not.
The calculator turns that into a daily gram target for your body weight and shows the gap versus what you eat now, so you know exactly how much to add.
Keeping muscle on a GLP-1 or any rapid weight-loss plan
If you’re losing weight with the help of a GLP-1 medication (such as semaglutide or tirzepatide), the same three levers apply — and they matter even more. Appetite suppression can make it genuinely hard to eat enough protein, and faster weight loss can mean a larger share of it comes from muscle. So protein, resistance training, and a sensible pace are exactly where to focus.
Important: this tool offers only general nutrition guidance. It does not advise on whether to use any medication, or on any dose or timing. Always follow your prescriber and a registered dietitian, and never change your treatment based on a calculator.
Don’t lose too fast
A good general target is to lose around or below 1% of your body weight per week. Beyond that, the convenience of fast results comes at the cost of more lean mass — which lowers your metabolism and can leave you "skinny-fat." If your pace is faster than that, the calculator flags it and suggests easing off (and, if a program set that pace, raising it with your provider).
Resistance training is non-negotiable
Protein supplies the building blocks, but resistance training is the signal that tells your body to keep the muscle. Two to three sessions a week covering the major muscle groups is plenty for most people losing weight — bodyweight, bands, or machines all count. You’re training to maintain, not to set records.
Frequently asked questions
How do I keep muscle while losing weight?
Eat enough protein (about 1.6–2.4 g/kg of body weight), do resistance training 2–3 times a week, and keep your loss to around or below 1% of body weight per week.
How much protein prevents muscle loss in a deficit?
Roughly 1.6–2.4 g of protein per kg of body weight per day, leaning higher if you’re losing quickly or are older. The calculator works out your exact target.
How do I keep muscle on Ozempic or a GLP-1 medication?
The nutrition principles are the same: hit your protein target despite reduced appetite, do resistance training, and keep a sensible pace. This is general guidance only — follow your prescriber and dietitian, and don’t change your treatment based on this tool.
Does losing weight fast cause muscle loss?
Yes — the faster you lose, the larger the share that tends to come from muscle. Keeping the pace near or below 1% of body weight per week, with enough protein and training, protects lean mass.
Do I have to lift weights to keep muscle?
Resistance training is the single most effective signal to retain muscle in a deficit. If you can’t lift, prioritize protein even more, but some form of resistance work is strongly recommended.
Sources & references
- Jäger R, Kerksick CM, Campbell BI, et al. "International Society of Sports Nutrition Position Stand: protein and exercise." J Int Soc Sports Nutr. 2017;14:20.
- Morton RW, Murphy KT, McKellar SR, et al. "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength." Br J Sports Med. 2018;52(6):376–384.
- Longland TM, et al. "Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss." Am J Clin Nutr. 2016.
- Cava E, Yeat NC, Mittendorfer B. "Preserving Healthy Muscle during Weight Loss." Adv Nutr. 2017;8(3):511–519.
Not medical advice. This result is an educational estimate from HealthyLifeStyles (Trusted Wellness), based on population formulas — not a diagnosis or treatment. Always consult a qualified healthcare professional about your health.
https://www.healthylifestyles.com/tools/muscle-preservation-calculator