Offseason Energy Surplus: How Big, and How Fast to Gain

An offseason exists to add muscle, and muscle needs an energy surplus to grow at its best rate. The research on the offseason energy surplus asks two things: how big the surplus should be, and how fast body weight should climb. The answer from controlled trials is consistent. A bigger surplus buys some extra muscle, and it buys a lot more fat. Past a moderate point, a faster offseason gain mostly adds fat.

What the evidence says

Surplus size in trained lifters (Helms et al., 2023). Trained lifters were randomized to eat at maintenance, a 5% energy surplus or a 15% energy surplus. All groups did the same resistance training three days a week for eight weeks. Twenty-one started and 17 finished. Muscle thickness and squat strength did not separate by group. The 15% group gained more bench-press strength. Skinfolds rose most in the larger-surplus group. Across everyone, the amount of body weight gained predicted the rise in skinfolds strongly (R² = 0.49). It predicted biceps growth only weakly (R² = 0.24). The authors concluded that a faster offseason gain mainly raises fat gain rather than muscle or strength. They recommend a surplus of 5-20% over maintenance, or a gain of 0.25-0.5% of body weight per week. More experienced lifters sit at the lower end of both ranges.