The Simple Answer (And Why It's Not That Simple)
To build muscle, you need to eat more calories than you burn. That's the simple answer. But "more calories" covers a lot of ground — from a modest 200-calorie surplus to eating everything in sight. The difference between those approaches determines whether you end up lean and muscular or just heavier.
Here's how to find the number that actually works for your body and your goal.
Step 1: Find Your Maintenance Calories (TDEE)
Before you can calculate a surplus, you need to know your baseline — the number of calories that keeps your weight stable. This is your Total Daily Energy Expenditure (TDEE).
TDEE includes:
- Basal Metabolic Rate (BMR): Calories burned at rest just to keep you alive
- Activity factor: Exercise, walking, work, general movement
- Thermic Effect of Food (TEF): Energy used to digest what you eat (roughly 10% of total intake)
Rough estimates by activity level (adjust based on real-world results):
| Bodyweight | Sedentary | Moderately Active | Very Active |
|------------|-----------|-------------------|-------------|
| 60 kg | ~1,800 | ~2,200 | ~2,600 |
| 75 kg | ~2,100 | ~2,600 | ~3,100 |
| 90 kg | ~2,400 | ~3,000 | ~3,500 |
These are estimates. The most accurate method is tracking your food intake and weight for 2–3 weeks without intentionally changing anything — if your weight is stable, you've found your maintenance.
Step 2: Set Your Calorie Surplus
Once you know maintenance, add a surplus. The size of that surplus matters.
The "Lean Bulk" Surplus: 200–350 Calories Above Maintenance
This is the sweet spot for most natural lifters. A modest surplus provides enough extra energy to support muscle synthesis without flooding your system with excess calories that get stored as fat.
What to expect: Roughly 0.25–0.5 kg of weight gain per month. This sounds slow, but the vast majority of that gain is lean tissue. After 6 months, you've built meaningful muscle without adding a significant fat layer you then need to cut through.
The "Aggressive Bulk": 500+ Calories Above Maintenance
This results in faster scale movement, but studies consistently show that muscle protein synthesis doesn't meaningfully increase with very large surpluses. The body has a ceiling for how fast it can build muscle. Calories above that ceiling become fat.
Aggressive bulks are rarely worth it for natural lifters. You end up spending the next several months cutting the fat you didn't need to gain, which is inefficient.
The Exception: Beginners
If you've been training seriously for less than 6 months, your body is unusually responsive to training stimulus. You may be able to build muscle even in a slight deficit (body recomposition), or at maintenance with adequate protein. Your first priority should be training hard and eating enough protein — aggressive bulking isn't necessary yet.
Step 3: Set Your Protein Target
Calories are the foundation, but protein is the building material. Without adequate protein, your body can't build new muscle tissue regardless of how many total calories you're eating.
Target: 1.6–2.2g of protein per kg of bodyweight per day.
For a 75 kg person, that's 120–165g of protein daily. Most people who aren't actively tracking fall significantly short of this — it's the single biggest nutritional mistake gym-goers make.
Good high-protein sources:
- Chicken breast / turkey breast
- Lean beef / bison
- Greek yoghurt / cottage cheese
- Eggs and egg whites
- White fish (tilapia, cod, haddock)
- Whey or casein protein powder
Practical tip: Build each meal around a protein source first, then add carbs and fats around it. This makes hitting your protein target much easier than trying to add protein retroactively to a carb-heavy meal.
Step 4: Handle Carbs and Fats
Once protein is set, the split between carbs and fat is flexible — but here's a sensible framework for a muscle-building phase:
- Carbohydrates (40–50% of remaining calories): Carbs fuel your training. Higher carb intake generally supports better gym performance, faster recovery, and improved muscle protein synthesis via the insulin response. Don't demonise them in a bulk.
- Fats (25–35% of remaining calories): Essential for hormones, including testosterone. Don't drop fat too low — consistently eating under 0.5g/kg bodyweight is associated with hormonal disruption.
Example for a 75 kg person aiming for 2,950 calories (TDEE 2,600 + 350 surplus):
- Protein: 150g (600 kcal)
- Fat: 90g (810 kcal)
- Carbohydrates: ~385g (1,540 kcal)
How Fast Should You Gain Weight?
Use this as a progress check:
- ~0.25–0.5 kg/month: Ideal for most intermediate lifters. Mostly lean mass gain.
- More than 1 kg/month: Surplus is likely too large. More fat gain than necessary.
- No weight change after 3+ weeks: Increase calories by 150–200.
Weigh yourself under consistent conditions (same time of day, after using the bathroom, before eating). Weight fluctuates day-to-day due to water, food volume, and hormones — use a weekly average, not a single daily reading.
Common Mistakes That Stall Muscle Growth
Eating in a deficit without realising it
This is surprisingly common. People think they're eating plenty, but when they actually track, they're 400–600 calories below maintenance. Without a surplus, muscle gain stalls for intermediate lifters regardless of training quality.
Too much protein, not enough total calories
Protein is important, but excess protein doesn't become extra muscle — it gets used for energy. Hitting your protein target is step one; hitting your total calorie target is step two. Both matter.
Forgetting that training creates the stimulus
A calorie surplus without progressive overload in the gym doesn't produce muscle. Extra calories give your body the resources to build muscle — but training gives it a reason to. If you're not adding weight, reps, or difficulty to your lifts over time, a surplus just becomes fat storage.
Stopping too early
A bulk requires patience. Four to six weeks is often not long enough to see meaningful changes in the mirror. Most successful bulks last 12–20 weeks minimum. Commit to the phase.
How Soma Tracks Your Calorie Target
Soma calculates your estimated TDEE based on your stats and training schedule, then applies a surplus appropriate for your goal. As your weight trends, it adjusts the recommendation — so you're not stuck with a static number that becomes inaccurate as your weight changes.
Photo calorie tracking makes logging food genuinely frictionless. Snap a photo of a meal, and Soma's AI estimates the macro and calorie breakdown instantly. No barcode scanning, no tedious database searches. For people who've tried and abandoned calorie tracking in the past, this removes the main friction point.
Your training data and nutrition data live in the same app — so Soma can connect the dots between your performance in the gym and whether your fuelling is adequate.
Download Soma free on the App Store and start fuelling your training properly.