To gain muscle, aim for at least 1.6 grams of protein per kilogram of body weight per day, get 45-60% of your calories from carbohydrates, and keep fat at 15-25% of total calories. But these numbers only work inside a caloric surplus, meaning you need to eat more than you burn. The size of that surplus, how you split your macros, and even how you distribute protein across the day all influence how much muscle you actually build.
How Many Calories You Need
You can’t build muscle without giving your body extra energy to work with. That means eating above your maintenance calories, the amount that keeps your weight stable. But bigger surpluses don’t build more muscle. A study comparing small and large energy surpluses in trained lifters found that when surpluses exceeded about 15%, the extra calories mostly added fat rather than accelerating muscle growth.
A surplus of 5-20% above maintenance is the sweet spot. If you’re new to lifting, you can afford to be on the higher end because your body responds more aggressively to the training stimulus. If you’ve been training for several years, stay closer to 5-10%. In practical terms, aim to gain about 0.25-0.5% of your body weight per week. For a 180-pound person, that’s roughly 0.5 to 1 pound per week. Gaining faster than that usually just means more body fat.
To find your maintenance calories, multiply your body weight in pounds by 14-16 (lower if you’re sedentary outside the gym, higher if you’re active). Then add your surplus on top. Track your weight for two to three weeks and adjust based on what the scale actually does.
Protein: The Most Important Macro
Protein provides the raw material your body uses to repair and build muscle fibers after training. A large meta-analysis in the Journal of Cachexia, Sarcopenia and Muscle found that intakes of 1.6 grams per kilogram of body weight per day or higher led to meaningful increases in lean body mass in younger adults doing resistance training. That works out to about 0.7-0.8 grams per pound of body weight, which is a simple number to remember.
For a 180-pound person, that’s roughly 130-145 grams of protein per day as a minimum target. Going somewhat higher, up to 1 gram per pound, provides a comfortable margin and won’t cause harm in healthy people. There’s little evidence that pushing beyond that range adds further benefit.
Spread Protein Across Your Meals
How you distribute protein throughout the day matters more than most people realize. Research published in The Journal of Nutrition found that eating about 30 grams of protein at each of three daily meals stimulated 24-hour muscle protein synthesis significantly more than eating the same total amount in a lopsided pattern (like 10 grams at breakfast, 15 at lunch, and 65 at dinner). The evenly distributed pattern produced roughly 40% more muscle-building activity at breakfast compared to the low-protein meal. Eating 90 grams of protein in one sitting was no more effective than eating 30 grams for triggering that muscle-building response.
The practical takeaway: aim for 30-40 grams of protein per meal across three to four meals. If you eat four meals, something like 40-40-40-30 works well. The key is avoiding the common habit of skimping on protein at breakfast and lunch, then trying to make up for it at dinner.
Best Protein Sources
Complete proteins, those containing all essential amino acids, are the highest quality for muscle building. Your best options include chicken breast, turkey, lean beef, pork loin, fish (salmon, tuna, trout), eggs, Greek yogurt, and cottage cheese. For plant-based eaters, soy products like tofu and tempeh, quinoa, and combinations of beans with grains provide complete amino acid profiles. Each protein-rich meal should contain enough of the amino acid leucine (around 2.5-3 grams) to fully activate the muscle-building process, which happens naturally when you hit that 30-gram protein threshold from quality sources.
Carbohydrates: Fuel for Training
Carbohydrates are your muscles’ primary fuel source during resistance training. They replenish glycogen, the stored energy in muscle tissue that powers your sets. Without adequate carbs, training intensity drops, and intensity is what drives muscle growth over time.
Older recommendations suggested 8-10 grams of carbs per kilogram of body weight for heavy anaerobic exercise, but a systematic review in Nutrients found this is likely excessive for most strength trainees. A range of 4-7 grams per kilogram per day is more appropriate for lifters focused on hypertrophy. For a 180-pound (82 kg) person, that translates to roughly 330-570 grams of carbohydrates daily. Where you land in that range depends on your training volume, your total calorie target, and how your body responds.
If you train with very high volume (11 or more sets per muscle group in a session) or train the same muscles twice in one day, prioritizing carbs around those sessions helps replenish glycogen faster. For most people lifting four to five times per week, landing around 4-5 grams per kilogram covers the bases without requiring you to force-feed rice.
Good carb sources for muscle gain include oats, rice, potatoes, sweet potatoes, whole grain bread, pasta, fruits, and beans. These provide not just energy but also fiber, vitamins, and minerals that support recovery.
Fat: The Floor You Shouldn’t Drop Below
Dietary fat plays a critical role in hormone production, including testosterone and other hormones involved in muscle growth. Cutting fat too low can compromise hormonal health and overall well-being. A review of nutritional recommendations for physique athletes suggested keeping fat at 15-25% of total calories for most people building muscle, with a strong caution against going below 10-15% for extended periods.
For someone eating 3,000 calories per day, 20% from fat equals about 67 grams. That’s not a lot of food, which is why fat is typically the macro you fill in last after setting protein and carbs. Prioritize sources that come with additional benefits: nuts, seeds, avocados, olive oil, fatty fish like salmon, and eggs. These provide healthy fats along with vitamins and minerals that support recovery and general health.
Putting It All Together
Here’s how to build your macro plan step by step, using a 180-pound person as an example:
- Step 1: Set calories. Estimate maintenance (say 2,700 calories) and add a 10-15% surplus, landing around 3,000 calories.
- Step 2: Set protein. At 0.8 grams per pound, that’s 145 grams (580 calories).
- Step 3: Set fat. At 20% of total calories, that’s 67 grams (600 calories).
- Step 4: Fill the rest with carbs. The remaining 1,820 calories go to carbohydrates, which is about 455 grams.
In percentage terms, this example works out to roughly 19% protein, 20% fat, and 61% carbohydrates. That aligns closely with the classic bodybuilding recommendation of 25-30% protein, 15-20% fat, and 55-60% carbs, with slight variations depending on individual calorie needs. Someone eating fewer total calories will naturally see their protein percentage climb higher even at the same gram target.
Realistic Muscle Gain Expectations
Even with perfect macros, muscle growth has biological speed limits. Beginner men in their first year of consistent training can expect to gain roughly 0.5-1 kilogram (1-2 pounds) of actual muscle per month during the early months. Beginner women typically gain about half that rate. After a year or two of training, those rates drop to roughly half again. Advanced lifters with several years under their belts gain muscle in grams per week, not pounds per month.
This matters for your macro plan because it sets realistic expectations for the scale. If you’re a beginner gaining more than 3-4 pounds per month total body weight, some of that excess is fat, and you may want to trim your surplus slightly. If the scale isn’t moving at all after two weeks, increase calories by 100-200 per day, primarily from carbohydrates, and reassess.