Macro partitioning
Increasing protein intake from 1.0 g/kg/day to 1.6 g/kg/day via egg white or whey protein supplementation does not further enhance physical performance (strength, endurance, aerobic capacity) in recreationally trained males and females undergoing high-intensity functional training (HIFT).
If you are already eating about 1 gram of protein per kilogram of body weight daily, adding extra protein supplements (like whey or egg white) will not make you stronger or more enduring during high-intensity functional training. Focus on your training consistency and total daily protein intake rather than buying extra supplements.
Protein supplementation did not affect any of these outcomes. Short-term HIFT improved exercise capacity, upper-body strength, and core endurance. However, increasing protein intake from 1.0 to 1.6 g/kg/day did not further enhance performance.
Why this rating
Randomized, triple-crossover, counterbalanced design with rigorous controls, though high dropout rate (25%) and short duration (6 weeks).
Source
Effects of Protein Supplementation During High-Intensity Functional Training on Physical Performance in Recreationally Trained Males and Females: A Randomized Controlled Trial
Christina Karpouzi et al. · Nutrients · 2025
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