How bulking actually works

Learn · Body composition · Explainer, Typed Supps

Eat a bit more than you burn and train hard. Without the training, you just gain fat.

Stage by stage

Modest surplus (~10–20% above maintenance): Enough spare material to build with. More does not build faster.
The signal (Mechanical tension): Progressive resistance training raises muscle protein synthesis for 24–48 hours. Without it, surplus becomes fat.
Substrate (~1.6 g/kg protein): Spread across 3–4 feedings, matching how long the synthesis response lasts.
The ceiling (Set by training age): 1–1.5% of bodyweight a month for a beginner, far less later. The surplus should match that, not an ambition.

What the evidence supports

Resistance training plus adequate protein increases muscle mass — strong evidence. Extremely well established.
Protein around 1.6 g/kg is sufficient to maximise the response — strong evidence. Consistent across pooled analyses, with limited benefit above roughly 2.2 g/kg.
A large surplus builds muscle faster than a modest one — insufficient evidence. Not supported. Larger surpluses increase fat gain without increasing lean gain.
Protein must be consumed within 30–60 minutes of training — insufficient evidence. Synthesis remains elevated for 24–48 hours; total daily intake is what matters.

Timing

Spread protein across the day. The post-workout window is far wider than it is usually sold as.

Time to effect

2–4 wks: Strength rises, largely neural.
8–12 wks: Visible size change begins.

Common myth

“Eat big to get big.” In reality: Growth is capped by training stimulus and training age, not by food. Past a modest surplus, the extra is fat you will have to diet off later.