This 12-week trial of 295 frail older adults (mean age 73.9) found that adding 20g daily whey protein during resistance training produced no overall benefit for muscle strength, mass, or physical performance compared to exercise alone. However, participants with baseline protein intake below 1.2g/kg body weight gained an additional 6.4kg in leg press strength, with those consuming under 0.8g/kg seeing even greater gains of 10.9kg.
These findings illuminate a critical threshold effect in protein supplementation that challenges the one-size-fits-all approach dominating current practice. The research suggests that protein interventions may be largely redundant for adequately-nourished frail elderly but transformative for those with marginal intake. This targeted approach could revolutionize how we prescribe protein therapy, moving from universal supplementation to precision nutrition based on individual baseline status. The study's strength lies in its real-world frail population and supervised training protocol, though the relatively short duration may have missed longer-term adaptations. This represents confirmatory evidence for personalized protein strategies rather than blanket supplementation recommendations.