Keep reading to learn who can benefit from a protein shake before bed, why you might want to consider this practice, and other practical tips.
In theory, a protein shake before bed should digest slowly overnight, providing your body with amino acids it can use to repair muscle tissue and speed up recovery after exercise.
But in reality, studies are mixed, and the potential benefits definitely depend on your goals.
Protein and Muscle Recovery
Some people drink a protein shake before bed to increase muscle-building and enhance recovery from resistance training or sports.
And while the research isn’t resoundingly positive, this reason is the one that’s best-supported by peer-reviewed evidence.
For example, during a 2012 study of 16 healthy young men, researchers had the men lift weights and then consume 40 grams of casein protein powder or a placebo drink before going to bed[*].
Notably, they found that the slow-acting casein protein increased key measures known as muscle protein synthesis and net protein balance[*]. In other words, the casein did appear to increase the rate of repair occurring overnight, as well as the young men’s ability to build muscle.
But other evidence calls the benefits of pre-bed casein protein into question.
One study found that a nighttime protein shake offered no added benefit when compared to a daytime shake[*].
And a 2019 review of studies concluded that taking your shake right before bed may be beneficial only if you train in the evening, at least according to current research[*].
Protein and Improved Performance?
If a protein drink before bed can potentially boost your body’s ability to repair itself overnight, you might expect to see direct improvements in athletic performance as a result.
A few recent studies have examined the performance effects of casein protein before sleep.
Two separate studies of men and women from 2018 found no measurable benefit on recovery, sports performance, or resistance exercise performance when participants drank a casein shake prior to bedtime[*][*].
And one of those studies also included whey protein in the comparison and found no benefit, either[*].
However, a small 2019 study of 10 professional soccer players did find a measurable and significant benefit in recovery, gauged according to both physical performance and muscle soreness, when participants consumed 40 grams of casein before going to bed after a soccer match[*].
Protein for Better Sleep?
Your diet can undoubtedly affect your sleep quality, and that includes protein ingestion.
However, there’s no direct evidence showing that a pre-bed shake, in particular, has any effect on sleep.
That said, numerous studies link overall dietary protein intake (and protein quality) to sleep quality:
- The authors of a series of clinical trials published in the American Journal of Clinical Nutrition concluded that “consumption of a greater proportion of energy [20-30% of overall calories] from protein while dieting may improve sleep in overweight and obese adults”[*]
- A study of nearly 500 women published in 2020 found that excess calories or inadequate protein consumption increased the risk of insomnia[*].
- Some researchers think whey protein, which is rich in the amino acid tryptophan, could improve sleep quality if taken close to bedtime–but there isn’t strong evidence from trials at this time[*].
If you aren’t sleeping well, overall protein intake is one of many factors you may want to experiment with for better sleep. But for sleep, protein timing (before bed versus during the day) and whether it’s slow-digesting protein don’t seem to be essential factors.
Protein and Weight Loss?
There’s strong evidence that consuming plenty of high-quality protein can enhance the weight loss process.
Here’s how it works:
- Protein appears to be more filling than other macronutrients, making portion control less challenging if you eat a relatively high-protein diet[*].
- A high-protein meal may reduce hunger hormones, further decreasing your appetite and making weight loss easier[*].
- Extra protein can help boost your metabolic rate, which can speed fat loss (as long as you don’t overeat calories)[*].
Eating an evening high-protein meal or having a nighttime protein shake instead of a typical meal might help prevent overeating before bed.
Still, the weight loss benefits of consuming extra protein right before bed are questionable.
Protein and Better Energy
If you’re fatigued, inadequate protein intake is one potential culprit.
According to a 2019 study of 1,590 participants published in the journal Nutrients, substituting protein in place of other macronutrients while keeping overall calories the same appears to decrease excessive daytime sleepiness[*].
If you don’t eat enough protein, you may become fatigued and experience decreased recovery and performance because your body can’t recover properly from training and competing[*].
Ultimately, though, the solution is simply to consume enough protein during the day. Adding in pre-bed protein is unlikely to be any more helpful than boosting your protein intake throughout the day.
All of the studies we’ve discussed have used casein protein or whey protein, both of which are dairy proteins.
Compared to whey protein, casein protein digests and absorbs more slowly, which is why some people prefer it for pre-bed usage[*].
As alternatives protein shakes, though, other high-quality protein sources could also enhance recovery when taken before bed:
- Cottage cheese: This high-protein snack is economical and naturally high in casein protein, making it a great alternative to protein shakes before bed[*].
- Greek yogurt or other dairy protein sources: Like cottage cheese, Greek yogurt is high in casein, plus it’s probiotic[*][*]. Win-win.
- Lean animal proteins: Meats like lean beef, ground beef, and chicken breast are a convenient, keto-friendly way to obtain high-quality protein before bed and still keep calories in check.
If in doubt, keep in mind that any high-quality protein source you’d generally consume during the day is probably acceptable before bed, too.
Protein vs. Carb Ratios
Many sports nutrition experts recommend a 2-to-1 ratio of carbs to protein for post-workout recovery, especially for athletes[*]. The primary purpose of the carbohydrates is to restore muscle glycogen for better athletic performance.
However, on the keto diet, consuming a protein shake with twice as much carbohydrate as protein content will quickly kick you out of ketosis.There’s also a chance that eating extra carbs before bed could lead to insulin resistance[*].
If you’re using the ketogenic diet for fat loss, you can still achieve progress on your exercise regimen following strict keto.
Either way, remember to leave the carbs out of your pre-bed shake if you care about your insulin sensitivity (and long-term health).
Lastly, most of the studies we’ve discussed here used around 25-40 grams of protein before bed, comparable to the amount of protein many active people eat per meal.
Therefore, as you measure out the protein for your pre-bed shakes, aim for 25-40 grams or an amount equivalent to your typical protein intake at meals, whichever is greater.
Slow-absorbing protein sources make the best pre-bed shakes.
The idea is to provide your body with all the amino acids it needs at night when you’re asleep (and therefore not eating).
Casein protein is the gold standard used in most studies.
The two most popular forms are micellar casein and calcium caseinate, and either one will work before bed. Sodium caseinate is less popular but offers similar properties to other casein proteins[*].
Stay away from hydrolyzed casein (casein hydrolysate) before bed, because it’s not a slow-absorbing protein powder[*].
And if you don’t have casein protein powder on hand, you can get creative and try blending some cottage cheese or Greek yogurt into your whey smoothies for a well-rounded, slow-absorbing pre-bed shake.
A protein shake before bed isn’t for everyone.
For the most part, this approach is unlikely to be helpful unless you’re an athlete, train with high intensity, or primarily want to build lean muscle mass.
Before you consider a pre-bed protein shake or high-protein meal, make sure to dial in the rest of your diet. Your calories, macronutrients, and daily protein intake need to be on point before you can really benefit it.And if you already consume plenty of protein during the day and aren’t lifting or exercising shortly before bed, the chances that you will gain a significant advantage from pre-bed protein are low, anyway.