A protein shake at 10.30 pm, just before the lights go out. Plenty of people do not dare. They are afraid of poor digestion, of waking up in the night, of sleeping badly. And when you train hard or are trying to lose fat, sleep is the last thing you want to damage.
I have already dealt with the weight question in Does eating late make you gain weight?. A small, protein-rich snack before bed does not slow down fat use. What remained was the question of sleep itself. A trial published on 20 October 2026 answers it.
A trial in elite athletes
The study comes from Florida State University, the team that started the first studies on protein before bed some fifteen years ago. Twenty-five female athletes from the top division of American college sport, aged 18 to 25, were recruited, and 21 finished.
Each one tested four drinks, three nights in a row each time. 40 g of casein, the slow milk protein. 40 g of alpha-lactalbumin, another milk protein. 40 g of carbohydrate. And a placebo with almost no calories. The first three provided 160 kcal. Neither the athletes nor the researchers knew which drink was served, and at least three days separated two trials. The drink was taken about two hours after the last meal and about 30 minutes before bed (Paterson et al., 2026).
Not a single worse night
Sleep was tracked with a WHOOP band. Total sleep time, time to fall asleep, sleep efficiency, resting heart rate, heart rate variability. Each morning, the athletes also rated the quality of their night, how long they felt it took them to fall asleep and how recovered they felt.
None of the drinks made a difference. Nights lasted between 7 h 28 and 7 h 37 depending on the drink, with sleep efficiency around 92%. Resting heart rate stayed at 53 or 54 beats per minute. How they felt in the morning did not move either. In six athletes wearing a glucose sensor, night-time blood sugar was no different from one drink to another.
So the fear does not hold up. In these athletes, 40 g of protein just before bed harmed neither sleep nor recovery.
What the study does not say
Three nights per drink is short. The participants were young elite athletes who already sleep more than seven and a half hours, not fifty-year-old women waking at 3 am. A wrist band is not a sleep recording in a lab. The glucose sensor only covered six people. And one of the authors is an unpaid member of the International Protein Board.
Above all, the study shows no harm. It does not show that the bedtime snack improves sleep or recovery. Those are two different things.
The protein ceiling per meal is a myth
You still hear that the body can only use 25 or 30 g of protein per meal and that the rest is wasted. It is wrong. In Maastricht in 2023, healthy young men were given 25 g or 100 g of protein after a full-body strength session. With 100 g, muscle protein building was stronger and lasted more than 12 hours. The body burned almost none of the surplus (Trommelen et al., 2023).
Building muscle is costly for the body, and it does not waste amino acids. A 40 g serving before bed is not a wasted serving.
Where this snack fits in your day
The foundation does not change. At least 30 g of protein in the morning and at least 30 g after 5 pm, every day and for everyone. In the morning, that is around 30 g for a woman and more like 40 to 50 g for a man. Evening protein is never optional, the only exception being prolonged fasting days. The bedtime snack comes on top of dinner. It does not replace it.
It is not useful for everyone. I recommend it case by case. The benefit is clearer when you train in the evening, and for the athlete who finishes an event at 10 pm and starts again at 6 am, it is sometimes a necessity. It also helps when you are far from your protein for the day. When dieting, a 25 g shake when evening hunger hits is a very good tool. If you have already reached your protein and do not train in the evening, you can skip it.
The figure from the studies is about 40 g of protein, for under 220 kcal, half an hour before bed. The form matters little. A large bowl of quark or cottage cheese, a plain Greek yoghurt with a scoop of protein powder, or a whey or casein shake in a small glass of water or milk. If it gives you heartburn, adjust it. If a big glass of liquid gets you up in the night, make a thick shake with little water, or have the quark instead.
Big late dinners are what spoil nights, not a small targeted snack. If you are hungry in the evening, eat. It will probably do nothing, or it will help.
This article is for information only and does not replace medical advice.