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So we all know good quality and quantity of sleep is vital for recovery and performance for pretty much every athlete out there. Non athletes benefit from quality sleep too - the effect of sleep deprivation or restriction on energy metabolism and weight gain isn’t well understood, but it’s thought that inadequate sleep can result in a reduced RMR and an increase in energy intake above normal levels the following day.

New muscle growth and existing muscle repair takes place when there’s an adequate availability of amino acids in the blood stream. This is similar to how our bodies store muscle glycogen when there is sufficient glucose in our bloodstreams. The difference is, our bodies don’t regulate amino acid concentrations in our blood like it does with glucose.

By this logic, a slow digesting protein providing a steady supply of amino acids into our blood whilst we sleep could potentially improve protein intake distribution, preventing amino acid levels from falling to a level which might risk catabolism.


Many people avoid large meals or calories altogether at night for fear of disrupting sleep or even for fear of inducing body fat accumulation. The research shows us that we need not be concerned about late night protein.

One example is a study conducted by Kinsey et al., (2016) on the effect of casein protein prior to sleep on fat metabolism in obese men. The study found that supplemental protein before bed doesn’t negatively affect lipolysis (release of body fat into the blood) or fatty acid oxidation (fat burned for energy). They summarized that:

‘Casein consumption before sleep did not affect fat or glucose metabolism, Resting Energy Expenditure, or suppress appetite in hyperinsulemic obese men. CAS may be consumed before sleep without impeding overnight or morning fat metabolism in young, obese men’

Whilst this research is specifically focused on young obese men, it provides a degree of insight into how we can look at protein consumption close to bed as a positive.

One strategy to help reach total daily protein targets, especially pre bed is the addition of a slow releasing protein like casein. Casein keeps a relatively high and stable level of aminoacidemia (concentration of amino acids in your blood) which is handy when you’re not eating for ~8 hours!


A 12 week study conducted by Snijders et al., (2015) on 44 young (22 year olds ±1yr) men where the men followed a progressive resistance training program found that the group that consumed a protein supplement containing 27.5 g of protein, 15 g of carbohydrate, and 0.1 g of fat every night before sleep following a prolonged resistance training session in the evening gained more muscle strength after resistance exercise training over this time period to a significantly greater extent than the placebo-supplemented group. One note to keep in mind for this particular study is that there is no mention of dietary intake standardization across the groups. E.g. we don’t know if calories over the time period were matched in any way in comparison to the individual needs of each athlete. As we know, overall caloric balance is a massive driver of muscle hypertrophy.

Now, whilst this is useful information and research backs it up – note that a lot of the research has been done on individuals with a final meal that has below 10g of protein normally. If you’re spreading your protein out evenly through the day and taking note of wanting to hit the leucine threshold by having anything above 20g protein in your final meal, you may benefit less than originally thought by having casein instead of your chicken. It’s highly likely that even if you hit your daily protein requirement, low levels of amino acids in your blood whilst you sleep can still compromise night time muscle growth!


Your total calories and daily protein intake are still going to be the strongest drivers for how much strength and muscle you gain from your training. With that said, having an even spread of protein over 24 hours can prevent amino acid concentrations from reaching low levels and in turn prevent catabolism/enhance anabolism.

Casein protein is a good option for a pre-bed protein as amino acids are gradually released into the blood stream over several hours, but it isn’t your only option! Other slow digesting protein sources include: cottage cheese, poultry, meat, and fish – pair these with some fats too and you further slow the rate of digestion.


Kinsey, A.W., Cappadona, S.R., Panton, L.B., Allman, B.R., Contreras, R.J., Hickner, R.C. and Ormsbee, M.J., 2016. The effect of casein protein prior to sleep on fat metabolism in obese men. Nutrients, 8(8), p.452.

Snijders, T., Res, P.T., Smeets, J.S., van Vliet, S., van Kranenburg, J., Maase, K., Kies, A.K., Verdijk, L.B. and van Loon, L.J., 2015. Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men. The Journal of nutrition, 145(6), pp.1178-1184.

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