Cutting vs Bulking: Setting Your Calories
Cutting vs bulking explained — how to set your calories for fat loss or muscle gain, how big a deficit or surplus to use, and when to switch.
Quick answer
To bulk (gain muscle), eat a small calorie surplus of about 5–15% above maintenance with high protein. To cut (lose fat), eat a deficit of about 10–20% below maintenance with high protein. Keep protein high in both phases to build or preserve muscle, and adjust based on real weekly progress.
"Cutting" and "bulking" just mean eating for fat loss or muscle gain. The key is getting the calorie direction and size right. Here's how to set them.
Find your maintenance first
Maintenance is the calorie level where your weight is stable. Track your intake and weight for two weeks; if weight holds, that's roughly your maintenance. Everything else is an adjustment from there.
Bulking: the surplus
A modest surplus (~5–15% above maintenance) builds muscle while limiting fat gain. Going huge ("dirty bulk") just adds fat you'll have to cut later. If you can't eat enough, a mass gainer can help — but food first.
Cutting: the deficit
A deficit of ~10–20% below maintenance drives steady fat loss (~0.5–1% of bodyweight per week). Bigger isn't better — aggressive deficits cost muscle and are hard to sustain. More in fat loss basics.
| Phase | Calories vs maintenance | Protein | Aim |
|---|---|---|---|
| Bulk | +5–15% | High | Muscle gain, minimal fat |
| Maintain | ~0% | High | Hold and recover |
| Cut | −10–20% | High | Fat loss, keep muscle |
Protein stays high either way
Whether cutting or bulking, keep protein toward the top of your daily range. It builds muscle in a surplus and protects it in a deficit. A protein powder makes hitting the target easy.
When to switch
Bulk until you're happy with your muscle (or fat is creeping up), then cut to reveal it. Beginners can often gain muscle and lose fat at once ("recomp") by eating near maintenance with high protein and training hard.
Browse protein and mass gainers to support either phase.
Supplements support — not replace — a balanced diet and consistent training. Claims are general in nature; always read the label and follow directions for use. If you're pregnant, breastfeeding or managing a medical condition, check with your GP first.