How Many Carbs and Fats Do You Need to Build Muscle?
Everyone talks about protein. But protein is usually only 20–25% of your calories. The rest comes from carbs and fat, and getting them right is what fuels your training and keeps your hormones healthy. Here's exactly how to set both.
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The free Fit Gorillas Macro Calculator works out your calories, protein, carbs and fats in 30 seconds, using the method in this article.
Why carbs and fat both matter
Protein provides the building blocks for muscle. Carbs and fat provide most of the energy you need to train hard and to grow.
- Carbs (4 calories per gram) are your muscles' main fuel for lifting. They're stored in your muscles as glycogen, which powers hard sets in the 6–15 rep range.
- Fat (9 calories per gram) is essential for hormones, including testosterone, and for absorbing vitamins A, D, E and K.
You need both. The question is how to split the calories between them. New to macros? Start with what are macros.
How much fat?
Official dietary guidance for adults puts fat at 20–35% of calories. For lifters, about 25% is a good default. It leaves plenty of room for carbs while keeping fat high enough for health.
Don't go too low. A 2021 meta-analysis found that men on low-fat diets had lower testosterone than men eating more fat. The effect was modest, and more research is needed, but it's a good reason not to drop much below 20% of calories or about 0.6 g per kg of bodyweight. A 2019 review of nutrition for bodybuilders in the off-season recommended 0.5–1.5 g of fat per kg per day.
Very high fat isn't better either. There's no strong evidence that eating more fat than you need builds more muscle. Every extra gram of fat is 9 calories you can't spend on carbs to fuel your training.
Get most of your fat from unsaturated sources: olive oil, nuts, nut butters, avocado, eggs and oily fish like salmon.
How many carbs?
Once protein and fat are set, carbs fill the rest of your calories. For most guys lifting 3–5 days a week, that lands around 3–6 g per kg of bodyweight. That 2019 review recommended at least 3–5 g per kg for bodybuilders gaining muscle.
Can you build muscle on low carb or keto? You can, but it seems to be harder. In an 8-week study of trained men eating in a calorie surplus, the group on a normal-carb diet gained about 1.3 kg of lean mass. The ketogenic group lost a little fat but didn't gain lean mass. If your goal is size, carbs make it easier.
Choose mostly whole-food carbs: rice, oats, potatoes, pasta, bread, fruit and beans. They bring fibre, vitamins and minerals with them. Aim for around 30–38 g of fibre a day.
Work out your numbers in 4 steps
- Calories: about 200–500 above your maintenance. See how many calories to build muscle.
- Protein: 1.6–2.2 g × bodyweight in kg. Multiply by 4 for calories. See how much protein you need.
- Fat: calories × 0.25, then divide by 9 for grams. Check it's at least 0.6 g per kg.
- Carbs: take the calories left over and divide by 4.
Protein: 2.0 g × 80 = 160 g (640 calories)
Fat: 3,000 × 0.25 = 750 calories ÷ 9 = 83 g (about 1 g per kg ✔)
Carbs: 3,000 − 640 − 750 = 1,610 calories ÷ 4 = about 403 g (about 5 g per kg)
Quick targets by bodyweight
Examples using the method above with 2.0 g of protein per kg and 25% of calories from fat. Use the calculator for numbers based on your height, age and activity.
| Bodyweight | Example calories | Protein | Fat | Carbs |
|---|---|---|---|---|
| 70 kg (154 lb) | 2,600 | 140 g | 72 g | 348 g |
| 80 kg (176 lb) | 3,000 | 160 g | 83 g | 403 g |
| 90 kg (198 lb) | 3,300 | 180 g | 92 g | 438 g |
What it looks like in food
| Good carb sources | Serving | Carbs |
|---|---|---|
| Rolled oats | 1/2 cup (40 g) | 27 g |
| White rice, cooked | 200 g | 56 g |
| Pasta, cooked | 200 g | 58 g |
| Potato, baked with skin | 200 g | 42 g |
| Banana | 1 medium (120 g) | 27 g |
| Bread, wholemeal | 2 slices (70 g) | 26 g |
| Honey | 1 tbsp (20 g) | 16 g |
| Good fat sources | Serving | Fat |
|---|---|---|
| Olive oil | 1 tbsp (14 g) | 14 g |
| Almonds | 1 handful (30 g) | 15 g |
| Peanut butter | 1 tbsp (20 g) | 10 g |
| Avocado | 1/2 avocado (80 g) | 12 g |
| Eggs, whole | 2 large (100 g) | 10 g |
| Salmon | 1 fillet (150 g raw) | 20 g |
| Cheddar cheese | 30 g | 10 g |
Values from USDA FoodData Central, rounded. See high-protein foods and the full diet plan for muscle gain for complete days of eating.
Does timing matter?
Less than you'd think. Your daily totals matter most. A few simple habits help:
- Have a meal with carbs and protein 1–3 hours before training so you have energy to lift.
- Eat a normal meal with carbs and protein after training. No need to rush it.
- Keep very fatty or high-fibre meals away from right before training if they sit heavy.
Bulking vs cutting
- Bulking: keep fat around 25% and let extra calories go mostly to carbs to fuel more training. See lean bulk vs dirty bulk.
- Cutting: keep protein high, keep fat at or above about 0.6 g per kg, and take most of the calorie cut from carbs. See how to cut without losing muscle.
Common mistakes
- Fearing carbs. Carbs don't make you fat. Eating more calories than you burn does.
- Going ultra low-fat. Under about 20% of calories for long periods may hurt your hormones.
- Forgetting cooking oils. One tablespoon of olive oil is about 120 calories, and it's easy to pour three.
- Eyeballing portions. Weigh your carbs and fats for a couple of weeks. See how to count macros.
Frequently asked questions
How many carbs should I eat to build muscle?
Most guys lifting 3 to 5 days a week do well on about 3 to 6 g of carbs per kg of bodyweight. The simplest method is to set protein and fat first, then fill the rest of your calories with carbs.
How much fat should I eat to build muscle?
About 25 percent of your calories, anywhere from 20 to 35 percent. Don't drop below roughly 0.6 g per kg of bodyweight, because very low-fat diets have been linked to lower testosterone.
Can you build muscle on a low-carb or keto diet?
You can, but it seems harder. In one 8-week study of trained men in a calorie surplus, a normal-carb diet built more lean mass than a ketogenic diet. If size is the goal, carbs make it easier.
Is fat or carbs better for building muscle?
You need both. Carbs fuel hard training, while fat supports hormones and health. Once fat is at a healthy level, extra calories are usually best spent on carbs.
Should I eat carbs before or after a workout?
Your daily total matters most. A meal with carbs and protein 1 to 3 hours before training helps you lift harder, and a normal meal afterwards is enough.
Do carbs make you fat?
No. Gaining fat comes from eating more calories than you burn overall, whether those calories come from carbs, fat or protein.
Know your numbers. Hit them daily.
Two steps to stop guessing and start growing.
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This article is general information for healthy adults and isn't medical advice. If you have a medical condition, check with your doctor or a dietitian first. Food values: USDA FoodData Central. Sources: Institute of Medicine (2005), Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Iraki et al. (2019), "Nutrition recommendations for bodybuilders in the off-season: a narrative review", Sports. Whittaker & Wu (2021), "Low-fat diets and testosterone in men: systematic review and meta-analysis of intervention studies", Journal of Steroid Biochemistry and Molecular Biology. Vargas et al. (2018), "Efficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trial", Journal of the International Society of Sports Nutrition. Kerksick et al. (2017), "International Society of Sports Nutrition position stand: nutrient timing", Journal of the International Society of Sports Nutrition. Related reading: What are macros? · How much protein to build muscle · How many calories to build muscle · How to count macros · Diet plan for muscle gain