Building muscle mass requires two things: the right training and enough calories. But eating more isn't the same as eating smart. The right macro split during a bulk determines whether you primarily build muscle or accumulate a significant layer of fat alongside it. This guide explains how to calculate your macros for bulking — with specific targets for protein, fat, and carbohydrates.
Key takeaways
- Bulking means a calorie surplus of 300 to 500 kcal per day — enough for muscle growth without excessive fat gain
- Protein: 1.6 to 2.0 g per kg of body weight — the evidence-based range for muscle protein synthesis
- Carbohydrates take priority during a bulk: they fuel intense training and support muscle recovery
- Keep fat at a healthy level (0.8 to 1.2 g/kg) for hormone balance — but don't make it the focus
- A "clean bulk" with a controlled surplus produces far less fat gain than a "dirty bulk"
What is bulking and why do you need a surplus?
Bulking is the phase where you intentionally eat more calories than you burn, with the goal of building muscle. Your body needs an energy surplus to synthesise new muscle fibres — you cannot build muscle optimally in a calorie deficit.
But more isn't always better. Too large a surplus leads to excessive fat gain. A common mistake is "dirty bulking": eating everything in sight. Yes, you grow — but a substantial portion of that growth is body fat.
A calorie surplus of 300 to 500 kcal per day is sufficient for most people to support muscle protein synthesis while keeping fat gain manageable. This is known as a lean bulk or clean bulk.
How much protein for muscle building?
Protein is the raw material for muscle tissue. Without enough protein — regardless of how hard you train — your body cannot build new muscle mass.
Sports nutrition research reviewed by EFSA and the International Society of Sports Nutrition points to a range of 1.6 to 2.0 g of protein per kg of body weight per day for people aiming to build muscle. This is considerably more than the baseline 0.83 g/kg recommendation for sedentary adults.
Practical guideline: start at 1.6 g/kg and increase toward 2.0 g/kg if you train intensively or have difficulty with recovery.
Why are carbohydrates so important during a bulk?
Carbohydrates are the macro most people underestimate when bulking. They provide the energy for resistance training — without adequate carbohydrates, you train less intensively, recover more slowly, and build less muscle.
When carbohydrate availability is too low, the body begins breaking down protein for energy — precisely the opposite of what you want during a muscle-building phase.
Prioritise slow-digesting complex carbohydrates:
- Pre-workout. Oats, brown rice, whole grain bread, pasta
- Post-workout. Rice, potatoes, sweet potato — for rapid muscle glycogen replenishment
- Throughout the day. Fruit, whole grain products, legumes
Macro calculation for bulking: worked example
Say you weigh 75 kg, your TDEE is 2,500 kcal, and you're bulking with a 300 kcal surplus (target: 2,800 kcal).
- Protein. 1.8 g × 75 kg = 135 g → 540 kcal
- Fat. 1.0 g × 75 kg = 75 g → 675 kcal
- Carbohydrates. 2,800 - 540 - 675 = 1,585 kcal → 396 g
That gives a split of 19% protein, 24% fat, and 57% carbohydrates. Carbohydrates dominate — and that's exactly right for a bulk.
Macro comparison: bulking vs. maintenance vs. fat loss
| Goal | Calories | Protein | Fat | Carbohydrates |
|---|---|---|---|---|
| Bulking | TDEE +300–500 | 1.6–2.0 g/kg | 0.8–1.2 g/kg | remainder (priority) |
| Maintenance | TDEE | 0.83–1.2 g/kg | 0.8–1.0 g/kg | remainder |
| Fat loss | TDEE –300–500 | 1.2–1.6 g/kg | min. 0.8 g/kg | remainder |
During a bulk, the emphasis shifts toward carbohydrates for training energy, while protein remains high to support muscle protein synthesis.
Clean bulk vs. dirty bulk: what's the difference?
Clean bulk: a controlled surplus of 300 to 500 kcal/day, primarily from minimally processed whole foods. Result: more muscle, less fat.
Dirty bulk: eating as much as possible with no regard for food quality. Muscles do grow in the short term — but alongside a large amount of body fat that requires a long, difficult cut phase to remove.
For most people, a clean bulk is the better strategy. It avoids the need for an extended, taxing fat-loss phase afterward.
How to track macros during a bulk
During muscle building, consistently hitting your protein target is at least as important as it is during fat loss. Consistency over weeks and months matters more than any single perfect day.
With Moveno, take a photo of your meal and instantly see its protein, carbohydrate, and fat content. No label reading required. Want to know more about protein's role in muscle growth? Read our guide on protein for muscle building.
Start bulking smarter today
Macros for bulking means a controlled surplus, protein at 1.6 to 2.0 g/kg, a healthy fat intake, and carbohydrates as the dominant energy source. Combine that with progressive overload in the gym and you give your body every building block it needs.
Download Moveno for free and track your daily macro split — including your protein target for the day.
Sources
- EFSA — Dietary Reference Values for protein — protein intake for muscle building and athletic performance
- PubMed — ISSN Position Stand: protein and exercise — 1.4–2.0 g/kg guideline for muscle mass in active individuals
- Voedingscentrum — Eiwitten (Protein) — protein function for muscle building and recovery
- Voedingscentrum — How many carbohydrates per day? — carbohydrates as primary fuel for exercise
