Scientific literature suggests that increasing the provision of dietary protein prior to sleep would represent an effective nutritional intervention to increase plasma amino acid availability, improve whole-body protein balance and augment overnight skeletal muscle reconditioning during overnight sleep (Res et al., 2012, Jager et al., 2017). These positive effects are even more relevant on exercise training days, particularly when exercising during the afternoon or night time (Trommelen et al., 2016). Indeed, the Position Stand of the International Society of Sports Nutrition (Jager et al., 2017) suggests that protein consumption in the evening before sleep might be an underutilized time to take advantage of protein feeding opportunity that can potentially help to maximise the training effect on body composition and performance. Additionally, the recently retrospective epidemiological study by Buckner et al. (2017) using data from the National Health and Nutritional Examination Survey to evaluate diets habits, indicates positive changes in lean mass and lower limb strength in participants consuming 20, 25 or 30 g of protein rich foods in the evening compared to those who consuming proteins food in the afternoon.
Although the aforementioned studies support the positive effect of eating more protein at night, only a few numbers of investigations have analysed the effect of adding protein supplementation before sleep to optimise long term training outcomes in active individuals. Burk et al., (2009) using a cross over design in 13 young men with no previous resistance training experience indicated that 70 g of protein (82% casein) consumed in the morning (10 am) and evening (10 pm) was more beneficial for increasing fat-free mass than consuming the supplement in the morning and afternoon (~3.50 pm) over an 8-week training and supplementation period. Although results are promising, the study by Burk and colleagues used only 1 week of washout period between treatments. Furthermore, the low sample size with no further effect size analysis makes no possible to reach conclusive evidence. Antonio et al., (2017) found no differences of ingesting casein (54 grams) in the morning (any time before 12 pm) or evening (90 minutes or less prior to sleep) on measures of body composition and exercise performance in trained men and women over an 8-week treatment period. Even though the mean differences for the fat-free mass observed for the evening group was four times greater compared than the calculated for the morning group (0.4 vs. 1.6 kg), further calculation of the effect sizes does not reveal any moderate effect for either the morning or evening group. In conclusion, even though, there is still no conclusive evidence, it seems that increasing protein consumption (≥0.25 to 0.4 g/kg) at night from food or slow absorption protein supplements (casein) would be an effective and recommendable strategy to maintain appropriate feeding and potentially improving training outcomes in athletes.
ANTONIO, J., ELLERBROEK, A., PEACOCK, C. & SILVER, T. 2017. Casein Protein Supplementation in Trained Men and Women: Morning versus Evening. Int J Exerc Sci, 10, 479-486.
BUCKNER, S. L., LOENNEKE, J. P. & LOPRINZI, P. D. 2017. Protein timing during the day and its relevance for muscle strength and lean mass. Clin Physiol Funct Imaging.
BURK, A., TIMPMANN, S., MEDIJAINEN, L., VAHI, M. & OOPIK, V. 2009. Time-divided ingestion pattern of casein-based protein supplement stimulates an increase in fat-free body mass during resistance training in young untrained men. Nutr Res, 29, 405-13.
JAGER, R., KERKSICK, C. M., CAMPBELL, B. I., CRIBB, P. J., WELLS, S. D., SKWIAT, T. M., PURPURA, M., ZIEGENFUSS, T. N., FERRANDO, A. A., ARENT, S. M., SMITH-RYAN, A. E., STOUT, J. R., ARCIERO, P. J., ORMSBEE, M. J., TAYLOR, L. W., WILBORN, C. D., KALMAN, D. S., KREIDER, R. B., WILLOUGHBY, D. S., HOFFMAN, J. R., KRZYKOWSKI, J. L. & ANTONIO, J. 2017. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr, 14, 20.
RES, P. T., GROEN, B., PENNINGS, B., BEELEN, M., WALLIS, G. A., GIJSEN, A. P., SENDEN, J. M. & LJ, V. A. N. L. 2012. Protein ingestion before sleep improves postexercise overnight recovery. Med Sci Sports Exerc, 44, 1560-9.
TROMMELEN, J., HOLWERDA, A. M., KOUW, I. W., LANGER, H., HALSON, S. L., ROLLO, I., VERDIJK, L. B. & LJ, V. A. N. L. 2016. Resistance Exercise Augments Postprandial Overnight Muscle Protein Synthesis Rates. Med Sci Sports Exerc, 48, 2517-2525.