Protein-enriched Meals At Breakfast Increase Muscle Accretion In Healthy Young Men Undergoing 12-week Resistance Training
Yasuda, Jun; Medicine & Science in Sports & Exercise: July 2020 - Volume 52 - Issue 7S - p 109
While daily protein intake has been reported to be essential for muscle regulation, the breakdown of daily protein intake in individuals is typically the lowest at breakfast and skewed towards dinner. Skewed protein intake pattern and inadequate protein intake at breakfast was reported to be a negative factor for muscle regulation, and no study has examined the effects of protein intake pattern at each meal on anabolic response such as muscle hypertrophy.
PURPOSE: This study aimed to examine whether a protein-enriched meal at breakfast to achieve adequate protein intake at all 3 meals is more effective for muscle accretion compared to typical protein intake pattern, skewed protein intake towards dinner.
METHODS: This 12-week, parallel-group randomized clinical trial included 26 men (means ± SEs; age, 20.8 ± 0.4 years; BMI, 21.8 ± 0.4 kg/m2). The participants were divided into 2 groups: HBR (n = 12), consuming a protein-enriched meal at breakfast to achieve adequate protein intake at all 3 meals; LBR (n = 14), consuming a provided meal at breakfast to achieve adequate protein intake at lunch and dinner. The participants performed 12-week supervised resistance training (RT) program 3 times/week (3 sets of 8-12 repetitions at 75-80% of one repetition maximum for 5 exercises). We used dual-energy X-ray absorptiometer to measure total fat-free mass (TotalFFM).
RESULTS: No significant difference in TotalFFM was observed between the 2 groups at baseline (HBR vs LBR: 52.4 ± 1.3 vs 53.4 ± 1.2 kg). After completing the 12-week diet plan and RT program, both the groups gained significant TotalFFM (2.1 ± 0.2 kg, 4.0 ± 0.4%), with the HBR group having greater changes in TotalFFM than the LBR group [HBR vs LBR, 2.5 ± 0.3 vs 1.8 ± 0.3 kg; P = 0.056; cohen’s d = 0.795 (Large effect size)].
CONCLUSIONS: Protein-enriched meal at breakfast to achieve adequate protein intake at all three meals is more effective than skewed protein intake at dinner for RT-induced muscle hypertrophy.