E. Horst

Supplementing with protein during strength training can increase gains in muscle size by approximately 27%, even when baseline protein intake is already considered adequate. The current RDA for protein, 0.8 grams per kilogram of body weight per day, is meant to prevent deficiency, not to optimize muscle growth or performance. Increasing intake to 1.5x the RDA leads to greater improvements in both muscle size and strength when combined with resistance exercise. Doubling the RDA is even better. Meta-analyses suggest that around 1.6 g/kg/day of protein is sufficient to maximize gains in muscle strength and fat-free mass, with potential (though smaller) benefits observed at higher intakes up to 2.2 g/kg/day for those aiming to fully optimize muscle growth and recovery (like athletes). This highlights how conservative the RDA truly is and why higher protein intakes are important, particularly for individuals engaging in regular strength training or other forms of physical activity.