If you're a guy who lifts weights regularly, eating 15% more calories than you burn might help you get stronger on the bench press compared to eating just a little extra or staying even, but it won’t give you an extra boost on squats or leg muscle growth.

What we've found so far is that a 15% calorie surplus may increase bench press strength more than a 5% surplus or maintenance in trained men who lift weights regularly [1]. The evidence we’ve reviewed leans toward this effect being specific to upper body strength, with no added benefit seen for squat strength or leg muscle growth [1]. Our analysis of the available research shows that when trained men eat 15% more calories than they burn, they may gain an advantage in bench press performance compared to eating at a smaller surplus or energy balance [1]. This finding is based on one assertion supported by 48.0 studies, with no studies refuting it [1]. While the number of supporting studies appears strong, we note that only one distinct claim was analyzed, which limits how broadly we can apply these findings at this time. We don’t yet know whether the effect is consistent across different training programs, diets, or individual body types. Also, the evidence doesn’t tell us how long the surplus needs to last, or whether the strength gains are due to increased muscle mass, improved recovery, or other factors. Our current analysis suggests that extra calories might help upper body strength gains more than lower body ones in trained lifters. But because the evidence is limited to one assertion, we can’t say for sure how strong or reliable this pattern is. Practical takeaway: If you're a trained lifter trying to get stronger on the bench press, eating about 15% more than you burn might help — but don’t expect the same boost in leg strength or squat performance.