To gain muscle, most people need roughly 1.4 to 2.0 grams of protein per kilogram of body weight each day, paired with a modest caloric surplus of about 350 to 500 calories above maintenance. The rest of your calories should come from carbohydrates and fats in a ratio that supports your training and hormone health. Those are the broad strokes, but the specifics matter, so let’s break each macronutrient down.
How Many Calories You Actually Need
Before you can set macros, you need a calorie target. Muscle growth requires more energy than your body burns in a day, but the surplus doesn’t need to be huge. Research published in Frontiers in Nutrition recommends a conservative surplus of roughly 350 to 500 calories per day for most people. Going much higher doesn’t accelerate muscle growth; it just adds more body fat.
To find your starting point, estimate your total daily energy expenditure. Multiply your body weight in pounds by 14 to 16, depending on how active you are outside the gym. Someone who sits at a desk all day and lifts three times a week would use the lower end. Someone with an active job or who trains five to six days a week would use the higher end. Add 350 to 500 calories on top of that number, and you have your target. For a 170-pound person with moderate activity, that works out to roughly 2,700 to 3,200 calories per day.
Track your weight weekly for two to three weeks. If you’re gaining about 0.5 to 1 pound per week, you’re in the right range. Faster than that and you’re likely adding unnecessary fat. Slower and you may need to bump calories up slightly.
Protein: The Most Important Number
Protein is the only macronutrient with a firm minimum for muscle growth. The International Society of Sports Nutrition’s position stand recommends 1.4 to 2.0 grams per kilogram of body weight per day for people who exercise regularly. In pounds, that translates to roughly 0.7 to 1.0 gram per pound of body weight. A 180-pound person would aim for 125 to 180 grams of protein daily.
Where you fall in that range depends on training experience and how hard you push in the gym. Beginners can build muscle effectively at the lower end. More advanced lifters, or anyone in a slight caloric deficit while trying to maintain muscle, benefit from the higher end. During a deliberate cut, protein needs climb even higher, potentially up to 1.4 grams per pound, to protect existing muscle mass.
How you distribute protein throughout the day also matters. Each meal should contain roughly 20 to 40 grams of protein, spaced every three to four hours. This keeps muscle protein synthesis elevated more consistently than cramming all your protein into one or two meals. A serving of 30 to 40 grams of a slow-digesting protein like casein (found in cottage cheese or casein powder) before bed can also boost overnight muscle repair.
Leucine: The Trigger for Muscle Building
Not all protein sources are equal. The amino acid leucine acts as a signal that switches on muscle protein synthesis. Each protein-containing meal should deliver at least 2 to 3 grams of leucine to cross that threshold. Animal proteins like chicken, eggs, dairy, and fish hit this easily in a typical serving. Plant-based eaters can reach it too, but they may need slightly larger portions or combinations of sources like legumes, soy, and grains to get there.
Carbohydrates: Fuel for Training
Carbohydrates don’t directly build muscle tissue, but they fuel the training sessions that do. They replenish glycogen, the stored energy your muscles burn through during sets of squats, presses, and rows. Without enough carbs, training intensity drops, and intensity is one of the primary drivers of muscle growth.
Older recommendations suggested 4 to 7 grams of carbs per kilogram of body weight for strength athletes, but a 2022 systematic review in Nutrients found that these numbers may be higher than most lifters actually need. For someone doing a typical hypertrophy program of 60 to 90 minutes, 3 to 5 grams per kilogram tends to be plenty. A 180-pound (82 kg) person would aim for roughly 250 to 400 grams of carbs per day. If you train twice a day or do very high-volume sessions with 11 or more sets per muscle group, push toward the higher end.
Timing carbs around your workout can help performance. Eating a carb-containing meal two to three hours before training consistently improves exercise performance in studies. A simple approach: have a normal meal with carbs and protein a couple hours before you lift, and another meal with carbs and protein within a few hours after.
Fat: The Floor That Matters
Dietary fat supports hormone production, vitamin absorption, and overall health. For muscle building specifically, the key concern is not eating so little fat that testosterone and other hormones suffer. Recommendations for athletes range from 20 to 35 percent of total calories, with physique-focused athletes sometimes going as low as 15 to 20 percent during specific phases.
A practical floor is around 20 percent of total calories for most people. On a 3,000-calorie diet, that’s about 67 grams of fat. Recent research suggests the link between dietary fat and testosterone is driven more by total energy availability than fat intake specifically, so as long as you’re eating enough calories overall, moderate fat intake is fine. Going extremely low fat for extended periods is not recommended.
Fat is the most flexible macronutrient for muscle gain. Once you’ve hit your protein target and set your carbs at a level that supports training, fill the remaining calories with fat.
Putting It All Together
Here’s how to calculate your macros step by step, using a 170-pound (77 kg) person eating 3,000 calories as an example:
- Protein: 1.6 g/kg = 123 g (492 calories). Round up to 150 g (600 calories) for a comfortable margin.
- Fat: 25% of total calories = 750 calories = 83 g.
- Carbohydrates: Remaining calories. 3,000 minus 600 minus 750 = 1,650 calories = 413 g.
As a percentage breakdown, that lands at roughly 20% protein, 25% fat, and 55% carbohydrates. This is a solid starting point, not a rigid prescription. Some people feel and perform better with slightly more fat and fewer carbs, or vice versa. The protein target is the one number worth protecting; carbs and fats can flex around it based on your preferences and how you feel in the gym.
Why These Numbers Are Ranges, Not Rules
Body composition, training age, genetics, sleep quality, and stress all influence how efficiently your body builds muscle. A lean 22-year-old who has been lifting for six months will respond differently than a 40-year-old carrying extra body fat who just started training. The research gives us ranges because individual variation is real.
The most productive thing you can do is pick a starting point within these ranges, stick with it for three to four weeks, and then adjust based on results. If you’re gaining weight too fast (more than a pound per week), trim 100 to 200 calories from carbs or fat. If your strength is stalling and you’re not gaining weight, add 200 calories, primarily from carbs. Protein intake up to 2.8 grams per kilogram has been studied in well-trained athletes with no negative effects on kidney function, so there’s a wide safety margin if you overshoot your protein target slightly.
The macro split that builds the most muscle is the one you can actually follow consistently. Hit your protein target, eat in a modest surplus, get enough carbs to train hard, and don’t slash fat to extremes. Everything else is fine-tuning.