Drinking a protein shake just before going to bed at night might increase gains in muscle-mass and strength following a resistance workout, according to researchers in the Netherlands.
In a preliminary study, they questioned whether this effect relates to increased protein intake, or whether any night-time beverage will work in this way.
Dr Tim Snijders, assistant professor at Maastricht University and lead author, said: "Several one-night studies have shown that pre-sleep protein intake increases muscle protein synthesis during overnight sleep in young adults. These have fuelled the idea that over a longer period, a pre-sleep protein supplement can maximise muscle mass gains during regular resistance exercise training."
Snijders proposes pre-sleep protein can be used to improve protein intake distribution over the day, saying: “Muscles can only grow and repair themselves when the building blocks – amino acids from protein – are available in the blood. This is because, unlike blood glucose, the body doesn’t store and release amino acids to maintain near-constant circulating levels.”
Snijders’ team also asked whether – if pre-sleep protein consumption allows muscles to take up more amino acids at night, this meant they would use less during the day, but found this was not the case, saying: "The muscle-building effects of protein supplementation at each meal seem to be additive. In one study we found that the consumption of ample amounts of protein before overnight sleep did not alter the muscle protein synthetic response to a high-protein breakfast the following morning.”
The team also asked whether this pre-sleep calorie consumption would lead to increases in body fat, but Snijders said the additional consumption of protein calories did not result in any increase in fat, mass despite the fact that exercise volume did not change.
He urged caution in interpreting the results, due to the low number of volunteers in the sample study, but said: “Supporting this finding, another group established that in 11 young active men a pre-sleep casein shake increased the rate of fat burning the following day. This might be because casein ingestion reduces the insulin response to subsequent meals, which pushes the body to use more fat."
Snijders says further study is needed to conclusively prove all these effects and has published his preliminary findings in the journal Frontiers in Nutrition.