Breakfast before resistance exercise lessens urinary markers of muscle protein breakdown in young men: a crossover trial
Jun Yasuda Nutrition Available online 21 November 2020,
Highlights
• Skipping breakfast before RE causes significant increase in 3-MH/Cr ratio after RE
• Skipping breakfast before RE increases MPB, seen by elevated urinary 3-MH levels
• Skipping breakfast before RE increases serum free fatty acid levels
• Breakfast intake before RE increases rate of insulin secretion and suppresses MPB
• Breakfast intake before RE is important for positive muscle protein balance
Objectives
Skipping breakfast prolongs the fasting state initiated after the last meal consumed the previous day and can have negative effects on muscle protein balance. This crossover trial aimed to examine the effects of skipping breakfast before a single bout of resistance exercise (RE) on muscle protein breakdown (MPB), as assessed using the urinary 3-methylhistidine/creatinine ratio (3-MH/Cr).
Research Methods & Procedures
Thirteen healthy young men, who habitually consumed breakfast (age 21.8 ± 1.1 years), were assigned to eating breakfast (EB) and skipping breakfast (SB) conditions. Participants consumed meat-free diets throughout the five-day experiment. On Day 5, individuals in the EB condition consumed breakfast (497 kcal) 2.5 h before RE (75% repetition maximum), whereas those in the SB condition consumed the same meal after dinner.
Results
In the two-way analysis of variance, significant interactions were observed with blood insulin and free fatty acid levels, and the 3-MH/Cr ratio (P < 0.05). We confirmed a significantly greater decrease in the insulin level pre-RE (P < 0.001; d = 3.281), and increases in the free fatty acid level pre-RE (P < 0.001; d = 1.437) and post-RE (P = 0.013; d = 0.811) and the 3-MH/Cr ratio 6 h (P < 0.001; d = 0.878) and 8 h (P < 0.001; d = 0.634) post-RE in the SB condition than in the EB condition.
Conclusion
Eating breakfast before RE can be beneficial for MPB suppression. The importance of breakfast consumption in terms of positive muscle protein balance is emphasized in sport fields.