Strategies to enhance weight loss with a high fat-to-lean ratio in overweight/obese older adults are important since lean loss could exacerbate sarcopenia. We examined how dietary protein distribution affected muscle protein synthesis during: energy balance (EB); energy restriction (ER); and ER plus resistance training (ER+RT). A 4-wk ER diet was provided to overweight/obese older men (66 ± 4 y, 31 ± 5 kg/m2) who were randomized to either a balanced (BAL: 25% daily protein/meal x 4) or skewed pattern (SKEW: 7:17:72:4% daily protein/meal; n = 10/group). Myofibrillar and sarcoplasmic protein fractional synthetic rates (FSR) were measured during a 13-h primed continuous infusion of L-[ring-13C6] phenylalanine with BAL and SKEW pattern of protein intake in EB, after 2-wk ER, and after 2-wk ER+RT. Fed-state myofibrillar FSR was lower in ER than EB in both groups (p < 0.001), but was greater in BAL than SKEW (p = 0.014). In ER+RT, fed-state myofibrillar FSR increased above ER in both groups and in BAL was not different from EB (p = 0.903). In SKEW myofibrillar FSR remained lower than EB (p = 0.002) and lower than BAL (p = 0.006). Fed-state sarcoplasmic protein FSR was reduced similarly in ER and ER+RT compared to EB (p < 0.01) in both groups. During ER in overweight/obese older men a BAL consumption of protein stimulated the synthesis of muscle contractile proteins more effectively than traditional, SKEW distribution. Combining RT with a BAL protein distribution 'rescued' the lower rates of myofibrillar protein synthesis during moderate ER.
- Copyright © 2015, American Journal of Physiology - Endocrinology and Metabolism