Data from 44 young men indicated that consuming protein supplements (casein hydrolysate: Peptopro, DSM) before sleep after resistance training increased skeletal muscle strength, compared with placebo. Specifically, leg extension and leg press strength increased by 23% and 25%, respectively, reported scientists from Maastricht University, the Dutch Olympic Committee, and the DSM Biotechnology Center.
“[P]rotein ingestion before sleep represents an effective dietary strategy to augment skeletal muscle mass and strength gains during prolonged resistance-type exercise training in healthy, young men,” wrote the researchers in the Journal of Nutrition.
The study was funded by DSM Food Specialties (Delft, The Netherlands) and the Dutch Olympic Committee.
According to background information in the Journal of Nutrition paper, it is already known that ingesting protein before sleep can increase muscle growth rates, but it still remained to demonstrate if protein before sleep can enhance the muscle adaptive response to resistance-type exercise training.
To answer this question, the Dutch researchers recruited 44 young men with an average age of 22 and randomly assigned them to two groups: One group received 27.5 grams of protein every night before sleep during a 12 week resistance training program, while the other groups received placebo and the same exercise program.
Results showed that both groups showed increases in muscle strength, but the gains were significantly greater in the protein-supplemented group, compared to the placebo group.
In addition, the area of the thigh muscles increased in both groups over time, with the greater increases in the protein group. (8.4 cm2 versus 4.8 cm2).
“The supplement was on average taken 3.9 h after cessation of exercise, allowing net muscle protein accretion during overnight sleep,” wrote the researchers. “This nutritional strategy was feasible and well tolerated by the participants.
“The protein supplementation effectively increased gains in muscle mass and strength despite the fact that participants in both the protein and the placebo groups already received a protein snack after each training session and consumed a relative high-protein diet.
“Consequently, it is quite remarkable that dietary protein supplementation before sleep further increased the gains in muscle mass and strength during prolonged resistance-type exercise training in these young, healthy adults.
“In the present study, ingestion of the protein supplement before sleep was not compared with other time points of ingestion. As such, we can only speculate on the surplus benefit(s) of the protein supplement being provided before sleep as opposed to other time points throughout the day.”
Source: Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.114.208371
“Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men”
Authors: T. Snijders, P.T. Res, J.S.J. Smeets, S. van Vliet, et al.