Free tool · Cantein Research
Protein Calculator for Weight Loss
How much protein to eat while you lose weight, from your weight, age, and body fat. Get a daily target in grams, how much to eat at each meal, and what the research on protein and weight loss shows.
Step 2
Your protein target
Enter your age and weight to see how much protein you need a day.
Quick answer
How much protein should I eat to lose weight?
A review of weight-loss trials supports 1.2–1.6 g of protein per kilogram of body weight a day, or about 0.54–0.73 g per pound (Leidy et al., 2015). For a 200 lb adult, that is about 109–145 g a day.
The calculator uses the top of that range, 1.6 g per kg. If you strength train while eating in a calorie deficit, it uses 2.2 g per kg. If you have a lot of weight to lose, add a body fat estimate so your target follows your lean mass instead of your total weight.
Both are well above the RDA of 0.8 g per kg, which is set to prevent deficiency, not to protect muscle while you eat less (Phillips et al., 2016).
Evidence
What the research shows about protein and weight loss
A 2015 review in the American Journal of Clinical Nutrition pulled together two decades of research on protein and weight loss (Leidy et al., 2015). It found:
- More fat loss, more lean mass kept. In meta-analyses of shorter, tightly controlled feeding studies, higher-protein calorie-restricted diets led to more weight loss and fat loss, and better preservation of lean mass, than lower-protein ones.
- A modest effect on fullness. After higher-protein meals, people felt fuller and had higher levels of satiety hormones. But in those trials, they didn’t eat less at their next meal.
- Sticking with it is what counts. Longer-term studies were mixed. People who kept to the higher-protein diet saw improvements; people who didn’t saw little change.
So protein isn’t a shortcut. It can help you hold on to lean mass and feel a little fuller while you eat less, if it’s a plan you can keep.
Methodology
Protein targets for weight loss
| Goal | Target | Range | Basis |
|---|---|---|---|
| Lose weight | 1.6 g/kg | 1.2–1.6 g/kg | Review of weight-loss trials (Leidy et al., 2015). We use the top of the range. |
| Lose fat while lifting | 2.2 g/kg | 2.0–2.6 g/kg | ISSN: 2.3–3.1 g/kg of lean mass while in a calorie deficit (Jäger et al., 2017) |
| Age 65+ | At least 1.2 g/kg | 1.0–1.5 g/kg | 1.0–1.2 g/kg for healthy older adults, more with exercise or illness (PROT-AGE, Bauer et al., 2013; ESPEN, Deutz et al., 2014) |
| RDA, for reference | 0.8 g/kg | – | The minimum to prevent deficiency in nearly all healthy adults (Institute of Medicine) |
The calculator also has targets for maintaining or building muscle without a calorie deficit. They are explained on our main protein calculator page.
Reference
Protein for weight loss by body weight
Grams of protein a day, using total body weight.
| Weight | Low end (1.2 g/kg) | Calculator target (1.6 g/kg) | Lifting in a deficit (2.2 g/kg) |
|---|---|---|---|
| 140 lb (64 kg) | 76 g | 102 g | 140 g |
| 160 lb (73 kg) | 87 g | 116 g | 160 g |
| 180 lb (82 kg) | 98 g | 131 g | 180 g |
| 200 lb (91 kg) | 109 g | 145 g | 200 g |
| 220 lb (100 kg) | 120 g | 160 g | 220 g |
| 240 lb (109 kg) | 131 g | 174 g | 239 g |
| 260 lb (118 kg) | 142 g | 189 g | 259 g |
| 280 lb (127 kg) | 152 g | 203 g | 279 g |
| 300 lb (136 kg) | 163 g | 218 g | 299 g |
At higher body weights, these totals can overstate what you need. The next section shows how the calculator adjusts for body fat.
Body fat
Current weight or goal weight?
Protein needs follow lean mass, not fat mass, so with a lot of body fat, a target from total weight runs high. If you enter a body fat above 25%, the calculator uses your lean mass divided by 0.75: the weight you would be at 25% body fat with your current muscle.
For example, a 250 lb person at 40% body fat has about 150 lb of lean mass. 150 ÷ 0.75 = 200 lb, so the calculator’s target is 145 g a day, instead of 181 g from total weight.
No body fat number? The tape-measure method estimates it from a few tape measurements.
Meals
How much protein per meal
The same review suggests at least about 25–30 g of protein per meal (Leidy et al., 2015). Hit that at breakfast, lunch, and dinner, then spread the rest of your target across meals and snacks. A 145 g target split across 3 meals is about 48 g each.
Our amino acid calculator checks each meal you log for protein and leucine, and a full day against all nine essential amino acids.
Calories
How many calories your protein takes up
Protein has 4 calories per gram (Institute of Medicine). At 145 g a day, protein is 580 calories: about a third of an 1,800-calorie day. That leaves less room than you might expect, so the calorie cost of each protein source matters.
Our guide to 100g of protein without whey compares what 25 g of protein costs in calories across 20 foods.
Strength training
Lifting while you lose weight
For strength training in a calorie deficit, the International Society of Sports Nutrition suggests 2.3–3.1 g of protein per kg of lean mass (Jäger et al., 2017). The calculator’s “Lose fat while lifting” goal uses 2.2 g per kg of body weight, which is about 2.4–2.9 g per kg of lean mass at 10–25% body fat.
Medication
On a GLP-1 medication?
If you take a GLP-1 medication like semaglutide or tirzepatide, a smaller appetite can make a protein target harder to reach. Our guide to protein and fiber on a GLP-1 walks through what a 2025 joint advisory says about protein, fiber, and keeping muscle. Your prescriber or dietitian sets your actual target.
FAQ
Frequently asked questions
How much protein should I eat to lose weight?
A review of weight-loss trials supports 1.2–1.6 g of protein per kg of body weight a day, or about 0.54–0.73 g per pound (Leidy et al., 2015). For a 200 lb adult, that is about 109–145 g a day. If you strength train while eating in a calorie deficit, the calculator uses 2.2 g per kg.
How many grams of protein per pound should I eat to lose weight?
About 0.54–0.73 g per pound of body weight, or about 1 g per pound if you strength train in a calorie deficit. If you have a lot of weight to lose, add a body fat estimate so the target is based on lean mass instead of total weight.
Should I use my current weight or my goal weight?
With a lot of body fat, a target from total weight overstates what you need, because fat mass needs little protein. Enter a body fat estimate and the calculator bases your target on lean mass: the weight you would be at 25% body fat with your current muscle. If you don’t know your body fat, the tape-measure method on our amino acid calculator page estimates it.
Does eating more protein help you lose weight?
In shorter, tightly controlled studies, higher-protein calorie-restricted diets led to more weight loss and fat loss, and better preservation of lean mass, than lower-protein ones. Longer-term results are mixed, mostly because of whether people stuck with the diet (Leidy et al., 2015).
How much protein should I eat per meal to lose weight?
At least about 25–30 g of protein per meal, according to a review of weight-loss research (Leidy et al., 2015). Spread the rest of your daily target across meals and snacks.
Do I need more protein if I lift weights while dieting?
Yes. For strength training in a calorie deficit, the International Society of Sports Nutrition suggests 2.3–3.1 g per kg of lean mass (Jäger et al., 2017). The calculator’s “Lose fat while lifting” goal uses 2.2 g per kg of body weight, which is about 2.4–2.9 g per kg of lean mass at 10–25% body fat.
Does the calculator store my data?
No. It runs in your browser, and nothing you enter is sent to Cantein or saved.
Is this medical advice?
No. It is an educational estimate for healthy adults. If you take a weight-loss medication, have kidney disease, are pregnant or breastfeeding, or follow a medically prescribed diet, talk with your clinician before changing your protein intake.
Source library
Sources
- Leidy et al. The role of protein in weight loss and maintenance.American Journal of Clinical Nutrition, 101(6), 2015.
- Jäger et al. International Society of Sports Nutrition position stand: protein and exercise.Journal of the International Society of Sports Nutrition, 14, 2017.
- Phillips, Chevalier & Leidy. Protein “requirements” beyond the RDA: implications for optimizing health.Applied Physiology, Nutrition, and Metabolism, 41(5), 2016.
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids.National Academies Press, 2005.
- Bauer et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group.Journal of the American Medical Directors Association, 14(8), 2013.
- Deutz et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group.Clinical Nutrition, 33(6), 2014.
Not medical advice. This calculator gives educational estimates for healthy adults 18 and older. Talk with your clinician before changing protein intake if you take a weight-loss medication, have kidney disease, are pregnant or breastfeeding, or follow a medically prescribed diet. Cantein makes hemp protein powder. Corrections: info@cantein.com.