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.
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 Is the Weight-Loss Macro
Any calorie deficit makes you lose weight. Protein determines what kind of weight. In studies of dieters eating too little protein, up to a third of the weight lost was lean mass. That is a bad trade: less muscle means a slower metabolism, a weaker body, and an easier path to regaining the fat.
The research minimum for preserving muscle in a deficit is 0.54g of protein per lb of body weight per day (1.2g per kg). If you also do resistance training, pushing towards 0.73g/lb (1.6g/kg) is better still. The calculator above gives you your personal number instantly.
Protein also fights for you on the appetite front. It is the most filling macronutrient per calorie, which is why high-protein diets consistently show better hunger control in a deficit. We cover the mechanisms in protein for weight loss.
Building Your Deficit Around Protein
- Set protein first, then let carbs and fat fill whatever calories remain
- Aim for 25 to 40g per meal; high-protein meal ideas and high-protein breakfast ideas make that concrete
- Choose lean protein sources so the protein does not drag extra calories with it
- Smart snacking helps; see our high-protein snacks for weight loss
- If you are losing weight with a GLP-1 medication, your situation is specific enough that we built a dedicated GLP-1 calculator
One Number to Track
Calorie counting works but burns people out. Tracking a single protein number is far easier to sustain, and in a deficit it is the number that matters most. The Protein Pal app is built around exactly that. Free on iOS and Android.