To gain muscle, eat about 10 to 20% more calories than you burn (for most people that is roughly 250 to 500 kcal a day above maintenance), get 1.6 to 2.2 g of protein per kg of body weight, and train with weights. Aim to gain about 0.25 to 0.5% of your body weight a week: for a 70 kg person that is about 0.2 to 0.35 kg. These are the ranges given in a 2019 review of off-season nutrition for bodybuilders; a bigger surplus mostly adds fat, not more muscle.
So the plan has three numbers: your maintenance calories, a moderate surplus on top, and protein and fat in grams. The rest of the calories come from carbohydrates.
Step 1: find your maintenance calories
Maintenance is the amount that keeps your weight stable. Estimate it with the guide on how many calories you need a day, then check it against reality: log what you eat for one or two weeks and see whether your weekly average weight stays the same. If it does, that intake is your maintenance. If you are slowly losing weight, your real maintenance is higher than you thought, and many people who "can't gain" are in exactly this situation.
Step 2: add a moderate surplus
The review by Iraki and colleagues suggests about 10 to 20% above maintenance for beginners and intermediate lifters, and a smaller 5 to 10% for advanced lifters, who build muscle more slowly. Slater and colleagues suggest a similar conservative start of roughly 360 to 480 kcal a day, then adjusting by results. In practice:
- Maintenance 2,000 kcal: eat about 2,200 to 2,400 kcal.
- Maintenance 2,300 kcal: about 2,550 to 2,750 kcal.
- Maintenance 2,600 kcal: about 2,850 to 3,100 kcal.
- Maintenance 3,000 kcal: about 3,300 to 3,600 kcal.
Start at the lower end. It is easier to add 100 to 200 kcal later than to remove fat you gained by eating too much. In the overfeeding studies that Slater's review describes, surpluses of around 1,000 kcal a day added much more fat than lean mass.
Step 3: set protein, fat and carbs
Protein: 1.6 to 2.2 g per kg of body weight a day, spread over 3 to 6 meals. A meta-analysis by Morton and colleagues found that extra protein stopped adding muscle gains at about 1.6 g/kg on average, so the upper part of the range is a safety margin for people who respond more, not a requirement. Fat: about 0.5 to 1.5 g per kg. Carbohydrates fill the remaining calories and support training; the review suggests at least 3 to 5 g per kg.
| Body weight | Protein a day (1.6 to 2.2 g/kg) | Fat a day (0.5 to 1.5 g/kg) | Carbs a day (from 3 to 5 g/kg) | Target gain a week (0.25 to 0.5%) |
|---|---|---|---|---|
| 60 kg | 96 to 132 g | 30 to 90 g | from 180 to 300 g | 0.15 to 0.3 kg |
| 70 kg | 112 to 154 g | 35 to 105 g | from 210 to 350 g | 0.18 to 0.35 kg |
| 80 kg | 128 to 176 g | 40 to 120 g | from 240 to 400 g | 0.2 to 0.4 kg |
| 90 kg | 144 to 198 g | 45 to 135 g | from 270 to 450 g | 0.23 to 0.45 kg |
To turn your own numbers into grams in one go, use the macro calculator; the guide on how to count macros explains how to track them through the day, and how much protein per day lists protein-rich foods.
A sample day at about 2,600 kcal
This example is for a 70 kg person with a maintenance of about 2,300 kcal, so the surplus is about 13%. Values are approximate and calculated from USDA FoodData Central per 100 g; rice and potatoes are weighed boiled, meat and fish cooked.
- Breakfast (about 680 kcal, 27 g protein): oats 80 g (dry) cooked in 300 ml of 2% milk, banana 120 g, peanut butter 20 g.
- Lunch (about 730 kcal, 50 g protein): chicken breast 130 g, white rice 300 g, cucumber and tomato salad 200 g with olive oil 10 g.
- Snack (about 470 kcal, 29 g protein): low-fat cottage cheese 150 g, whole grain bread 60 g, apple 150 g, walnuts 20 g.
- Dinner (about 730 kcal, 44 g protein): baked salmon 150 g, boiled potatoes 300 g, broccoli 200 g, olive oil 10 g.
Total: about 2,600 kcal, 150 g of protein (about 2.1 g/kg), 85 g of fat and 310 g of carbohydrates. If your number is lower, start from the 2,500 kcal meal plan and remove the snack bread or part of the rice. If it is higher, add a fourth meal such as Greek yogurt with oats and fruit.
How to check that it works
Weigh yourself in the morning, after the toilet and before eating, three to seven times a week, and compare weekly averages. Then adjust every two to three weeks:
- Gaining less than the target or not at all: add 100 to 200 kcal a day, mostly from carbohydrates.
- Gaining within the target: keep the plan.
- Gaining faster and the waist grows quickly: remove 100 to 200 kcal a day.
Expect the first week to show more on the scale: more food and more carbohydrates mean more water and glycogen in the body. That is normal and is not fat. Also track your lifts: if weights in the main exercises are slowly going up while body weight rises at the target pace, the surplus is doing its job.
If you struggle to eat enough
- Add calorie-dense foods rather than bigger plates: nuts, peanut butter, olive oil, dried fruit, cheese, whole milk.
- Drink part of the calories: milk, kefir or a smoothie with oats and banana are easier than another full meal.
- Eat four or five times a day instead of two large meals.
- Keep a log for two weeks. People who think they eat "a lot" often eat much less on rest days; a calculated daily target and a log show the gap.
Common mistakes
- "Dirty bulking": eating anything in large amounts. Weight goes up fast, but much of it is fat that you will later have to lose.
- Too much protein, too few carbs: above about 2.2 g/kg extra protein adds little, while carbohydrates fuel training.
- No progressive training: a surplus without lifting heavier over time mostly adds fat.
- Judging by one day: water and salt move the scale by up to a kilogram; look at the trend.
When to ask a doctor first
These ranges are for healthy adults who train. If you have kidney disease, diabetes, an eating disorder or another medical condition, or if you are under 18, talk to your doctor or a registered dietitian before changing how much you eat. If you are losing weight without trying, see a doctor rather than simply eating more.