Dividing adequate daily protein intake, including protein before bed, helps muscles repair, adapt, and build. The goal is to provide a continued amino acid source throughout the day and night for optimal training gains. A pre-sleep protein routine can help.
Advantages for Recovery and Body Composition
Protein intake has been shown to improve muscle protein synthesis (MPS), increase lean mass, reduce fat mass, and lower body fat percentage 1,2,3 Eating adequate amounts of protein, especially casein before bed, will lead to an extended period of available amino acids for MPS to occur. Pre-sleep protein studies illustrate improvements in several performance markers2:
- Overnight MPS
- Strength gains
- Muscle mass increase in the quadriceps
- Fat metabolism
- Higher morning resting metabolic rate
- Sleep quality has not been shown to change with the addition of pre-sleep protein4
Eating before sleep is often discouraged in articles about health. A dinner sized meal or large snack of sweet, salty or fatty foods before bed may hinder sleep quality and contribute to weight gain5. Eating before bed has been shown to be detrimental in certain scenarios. Anyone overeating, binge eating, experiencing heartburn or indigestion, or eating to relax or stay occupied at night should discuss their individual care with a medical professional. For athletes looking to improve performance, protein meals before bed have been specifically studied — and shown to provide a benefit.
Slow v. Fast Protein
Because MPS drops to baseline within 2-3 hours after eating, it is generally recommended that protein feedings occur approximately every 3 hours while awake. What happens during sleep? It depends on what is eaten.
Consuming a spoonful of sugar will quickly increase blood sugar levels. A carrot still contains sugar, but breaks down slower in the body with a prolonged and more modest rise in blood sugar. Similarly, whey and casein have different absorption rates. Whey is considered a “fast protein” while casein has a slower rate of gastric emptying, making it a “slow protein”6. Eating casein provides a more consistent level of amino acids — fueling muscle repair and metabolism for a longer period of time.
Another way to think about this: eating a high casein meal immediately after working out may not be best. “Slow protein” won’t quickly break down and provide immediate building blocks for muscles. Opt for a “fast protein” post-workout recovery meal like whey and a “slow protein” like casein 30 minutes before bed. This will yield a rapid intake of protein when muscles quickly need fuel, then provide a slower metabolic response with a prolonged supply of amino acids during sleep.
The literature suggests consuming 30–40 g of casein protein, 30-min prior to sleep and at least two hours after the last meal (dinner).
While casein intake before bed may be optimal, it is difficult to know exactly what 30-40 g of casein protein looks like unless a casein protein powder is consumed. The casein content in foods is not currently listed. Whey and casein proteins are contained in both cow and goat milk. Dairy products that have had the whey (in the liquid portion of milk) removed have a higher casein content. Hard cheeses contain more casein per serving than soft cheeses.
Table 1: Protein content in high casein foods
Greek Yogurt, nonfat, plain
Gouda Cheese, diced
Cheddar Cheese, diced
Cottage Cheese, Low-fat, 2%
Milk, Cow, 2% fat
* Lower casein content
Dosing casein is, at best, approximate. Getting adequate daily protein intake, regardless of a dairy, meat, fish, egg, or plant-based source, to balance an athlete’s higher requirements is the goal. It is O.K. to skip pre-sleep mealworm protein — one study concluded that it did not improve strength or body composition.
Pre-Sleep Protein Limitations
There are gaps in the available data. Most studies were done on whey protein or casein protein with a small sample size. Data are limited on the effects of plant-based protein. Many studies on pre-sleep protein had conflicting or inconclusive findings.
There were no gains seen with pre-sleep protein in:
- Running performance
- Time trial performance
- Training volume
- Blood biomarkers
- Next-morning resistance exercise volume
Future work is needed in several pre-sleep nutrition areas: optimal amino acid content of pre-sleep protein intake; benefits with food intake vs. liquid meals such as protein powder; exercise timing throughout the day; and differences between A1 and A2 type milk. There are conflicting pre-sleep protein study results seen with different age groups; post-exercise muscle soreness protocols; strength gain outcomes; and meals containing mixed protein sources or protein and carbohydrate sources.
Regardless of an individual’s sports performance goals, adding 30-40g of pre-sleep protein will promote MPS, strength, and fat metabolism. The literature has primarily focused on the comparison of whey protein and casein protein, but consuming adequate levels of any protein is better than not eating enough protein to fuel exercise and recovery. Casein is digested slower than whey, further increasing the metabolic effect of available amino acids during sleep — and improving performance.
If you want to learn more please refer to “Pre-sleep casein protein ingestion: new paradigm in post-exercise recovery nutrition” Kim (2020). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451833/
Many of the scientists who author the citied studies also teach courses on GPNi-TV. To learn from the leaders in the field of sports nutrition, see the GPNi education tab. https://gpni.fit/gpni-tv/
By Melissa Shays, ND, LAc, CISSN
1.Jäger, R., Kerksick, C.M., Campbell, B.I. et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017 June 20; 14:20. doi:10.1186/s12970-017-0177-8. https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8#citeas
2.Antonio J, Candow DG, Forbes SC, Ormsbee MJ, Saracino PG, Roberts J. Effects of Dietary Protein on Body Composition in Exercising Individuals. Nutrients. 2020 Jun 25;12(6):1890. doi: 10.3390/nu12061890. PMID: 32630466; PMCID: PMC7353221. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353221/#B71-nutrients-12-01890
3.Kerksick CM, Arent S, Schoenfeld BJ, Stout JR, Campbell B, Wilborn CD, Taylor L, Kalman D, Smith-Ryan AE, Kreider RB, Willoughby D, Arciero PJ, VanDusseldorp TA, Ormsbee MJ, Wildman R, Greenwood M, Ziegenfuss TN, Aragon AA, Antonio J. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017 Aug 29;14:33. doi: 10.1186/s12970-017-0189-4. PMID: 28919842; PMCID: PMC5596471. https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0189-4
4.Tim Snijders, Jorn Trommelen, Imre W. K. Kouw, Andrew M. Holwerda, Lex B. Verdijk, Luc J. C. van Loon. The Impact of Pre-sleep Protein Ingestion on the Skeletal Muscle Adaptive Response to Exercise in Humans: An Update. Frontiers in Nutrition, 2019; 6 DOI: 10.3389/fnut.2019.00017 https://www.frontiersin.org/articles/10.3389/fnut.2019.00017/full
5.St-Onge MP, Roberts A, Shechter A, Choudhury AR. Fiber and saturated fat are associated with sleep arousals and slow wave sleep. J Clin Sleep Med 2016;12(1):19–24. https://jcsm.aasm.org/doi/10.5664/jcsm.5384
6.Kim J. Pre-sleep casein protein ingestion: new paradigm in post-exercise recovery nutrition. Phys Act Nutr. 2020 Jun 30;24(2):6-10. doi: 10.20463/pan.2020.0009. PMID: 32698256; PMCID: PMC7451833. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451833/