Protein Calculator for Weight Loss
Calculate how much protein you need per day while losing weight. Enough protein in a calorie deficit is what makes the difference between losing fat and losing muscle. Same formula as the Protein Pal app.
Medical Disclaimer
This calculator provides general nutritional guidance based on scientific research. Before making significant changes to your diet or protein intake, especially if you have existing health conditions, kidney problems, or are pregnant or breastfeeding, please consult a qualified healthcare provider. If you are on prescription medication, follow your prescriber's advice first.
Why Protein Decides What Kind of Weight You Lose
Any calorie deficit makes you lose weight. Protein helps decide whether it comes from fat or muscle. In a meta-analysis of randomized trials, higher protein diets during calorie restriction preserved more lean mass and removed more fat than standard protein diets (Wycherley et al., American Journal of Clinical Nutrition, 2012). That matters beyond the scale: muscle supports your metabolism, strength and blood sugar control, and keeping it makes regain less likely.
A review in the American Journal of Clinical Nutrition recommends 1.2 to 1.6g/kg of body weight a day for weight loss and keeping it off (Leidy et al., American Journal of Clinical Nutrition, 2015), and the 2025 joint advisory from four US nutrition and obesity societies notes the same range (Mozaffarian et al., American Journal of Clinical Nutrition, 2025). The calculator uses the 1.2g/kg lower bound, or 1.6g/kg if you strength train.
Daily Protein for Weight Loss by Body Weight
| Body weight | Lose weight (1.2g/kg) | Lose weight and strength train (1.6g/kg) |
|---|---|---|
| 120lb (54kg) | 65g | 87g |
| 140lb (64kg) | 76g | 102g |
| 160lb (73kg) | 87g | 116g |
| 180lb (82kg) | 98g | 131g |
| 200lb (91kg) | 109g | 145g |
| 220lb (100kg) | 120g | 160g |
| 240lb (109kg) | 131g | 174g |
| 260lb (118kg) | 142g | 189g |
| 280lb (127kg) | 152g | 203g |
| 300lb (136kg) | 163g | 218g |
Strength Training Raises Your Target
If you strength train twice a week or more, the calculator lifts your target to 0.73g/lb (1.6g/kg). That is the top of the weight loss range and the level the muscle building research was done at, in people training at least twice a week (Morton et al., British Journal of Sports Medicine, 2018). Lifting while you lose weight is the best way to keep muscle, and the extra protein gives it something to work with. Tick "I strength train 2+ times a week" above to see your number.
Losing Weight on a GLP-1, or Over 65
- On Ozempic, Wegovy, Mounjaro or Zepbound: the minimum is the same 1.2g/kg, and a 2025 expert consensus recommends 1.2 to 1.5g/kg during GLP-1 weight loss (Sievenpiper et al., Obesity Pillars, 2025). The GLP-1 protein calculator covers it in detail.
- Over 65: muscle loss with age makes protein even more important while dieting. Expert groups recommend at least 1.0 to 1.2g/kg for healthy older adults even when not losing weight (Bauer et al., PROT-AGE Study Group, JAMDA, 2013), so treat 1.2g/kg as a floor.
Building a Deficit Around Protein
- Set protein first, then let carbs and fat fill the calories that remain
- Aim for 25 to 40g per meal: 100g of roasted chicken breast has 31g, a cup of 1% cottage cheese 28g and a 6oz pot of plain nonfat Greek yogurt 17g (USDA FoodData Central)
- Choose protein that does not bring many calories with it. Nonfat Greek yogurt and 1% cottage cheese give about 17g of protein per 100 calories, level with chicken breast (dairy protein data)
- Plan your snacks: our high protein snacks for weight loss and high protein breakfast ideas help, and the verified best protein bars rankings show which bars give the most protein per calorie
For the mechanisms, see why protein is important for weight loss.
One Number to Track
Counting every calorie works for some people but burns many out. Tracking one protein number is easier to sustain, and in a deficit it is the number that protects your muscle. Protein Pal uses this same formula, with optional calorie tracking if you want it. It is free to download on iOS and Android, and manual logging is free.
Common Questions
- How much protein should I eat to lose weight?
- At least 0.54g per lb of body weight per day (1.2g/kg) while in a calorie deficit, the lower end of the 1.2 to 1.6g/kg range recommended for weight loss. A 200lb (91kg) person needs about 109g a day, or about 145g if they strength train.
- Should I eat more protein if I lift weights while dieting?
- Yes. If you strength train twice a week or more, the calculator uses 0.73g/lb (1.6g/kg), the top of the weight loss range and the level shown to support muscle in people who train.
- Does protein help with weight loss itself?
- It helps in two ways. Protein is the most filling macronutrient, which makes a deficit easier to stick to, and in trials higher protein diets during calorie restriction kept more lean mass and lost more fat than standard protein diets.
- Should I use my current weight or goal weight?
- Use your current weight, as the research does. If you have a lot of weight to lose and the number feels unrealistic, ask a dietitian about using an adjusted weight. Recalculate as your weight comes down.
- Is the target different on Ozempic or Mounjaro?
- The minimum is the same 1.2g/kg. A 2025 expert consensus recommends 1.2 to 1.5g/kg during GLP-1 weight loss. Our GLP-1 protein calculator explains the details.