“Eat everything in sight” has been gym advice for decades. But is a massive surplus actually better for building muscle?

Dirty bulking

A dirty bulk means eating as much as possible — often 500-1,000+ kcal over maintenance — with little concern for food quality. Muscle gain is limited by how fast your body can synthesise new tissue, so beyond a point the extra energy is stored as fat.

Lean bulking

A lean bulk uses a smaller surplus (around 200-300 kcal) from mostly whole foods. Studies comparing surplus sizes in trained lifters found larger surpluses produced more fat gain without meaningfully more muscle.

Recommended weight-gain rates

• Beginners: ~1-1.5% of body weight per month.
• Intermediate: ~0.5-1% per month.
• Advanced: ~0.25-0.5% per month.

Tracking it

Weigh yourself daily under the same conditions and watch the 7-day average. Take monthly progress photos and measurements. If your average weight rises faster than the targets above, trim 100-150 kcal; if it stalls for two weeks, add 100-150 kcal.

The verdict: for most people a lean bulk produces nearly identical muscle gain, far less fat to lose afterwards and better health markers.