It’s claimed that casein, a slowly digested dairy protein, enhances overnight muscle protein synthesis.Mitch Hrdlicka/Getty Images
If you’re trying to put on muscle, you probably pay close attention to protein. Combined with resistance training – the most potent stimulus for increasing muscle mass and strength – getting enough protein can help you realize this goal.
Is there an optimal time, though, to eat that protein?
Perhaps you’ve heard that consuming protein immediately after a workout boosts muscle-building. Or that a protein shake before you sleep is best to enhance exercise-induced muscle gain.
Turns out, evidence doesn’t support meticulously timing your protein shake around workouts or bedtime.
Here’s what to know about the link between protein timing and muscle mass and strength.
How much protein for muscle-building?
Amino acids, the building blocks of protein, are used to repair and build muscles tissues that break down during exercise. Replacing valuable muscle protein helps you recover faster and train harder.
If your goal is to gain muscle, you need to consume twice as much protein each day as a sedentary person does.
According to a 2018 review of 49 randomized controlled trials, a daily protein intake of 1.6 g per kilogram of body weight (0.73 g protein per pound) significantly increased muscle strength and size.
An 82 kg (180 lb.) person, then, would need to consume 131 g of protein per day. For perspective, six ounces of chicken have 38 g of protein, two large eggs have 12.5 g, one cup of Greek yogurt has 24 g, on -cup of chickpeas has 15 g and one serving of protein powder typically delivers 20 to 30 g.
The analysis, which included 1,863 healthy adults who participated in resistance training two to five days a week for at least six weeks, concluded that consuming protein beyond this amount did not result in further gains in muscle mass.
Is timing really everything?
The idea that, in order to optimize muscle growth, it’s necessary to consume protein (and carbohydrates) immediately after a strength workout has been around for some time.
The theory goes that doing so within a 30-minute “anabolic window” will increase muscle protein synthesis, reduce muscle protein breakdown and replenish muscle glycogen (carbohydrate) stores. Miss this eating window and recovery won’t be ideal.
The evidence, however, doesn’t support this strategy. Studies have found that the window of opportunity for protein intake to support muscle growth is quite wide.
A 2013 review of 43 trials found that timing protein intake within an hour of training sessions didn’t have a significant effect on muscle growth. Instead, the strongest predictor of increased muscle size was total daily protein intake.
What matters most, it seems, is that you consume the protein you need over the course of a day.
To maximize muscle protein synthesis, research also suggests it’s important to distribute your protein over three meals rather than skewing it to one meal.
Is a bedtime protein shake helpful?
Drinking a casein protein shake before bedtime is also promoted to maximize the muscle gains of resistance training. It’s claimed that casein, a slowly digested dairy protein, enhances overnight muscle protein synthesis.
A 2015 study of 44 young men participating in a 12-week weightlifting program found that those given a presleep shake of 30 g of casein and 15 g of carbohydrate gained more muscle compared to those who consumed a calorie-free drink.
The researchers weren’t certain, however, if the observed muscle benefits were due to the timing of the protein, or simply a higher total intake of protein and calories.
A 2018 study conducted in older men showed no effect of a bedtime casein on muscle mass and strength during a resistance training program. Another study in young men found that consuming a casein supplement either early in the day or shortly before bed were both effective for increasing muscle, suggesting that it’s total daily protein that matters, not timing.
Bottom line
According to Stuart Phillips, a professor in kinesiology at McMaster University and a Tier 1 Canada Research Chair in Skeletal Muscle Health and Aging, “nutrient timing has an almost immeasurable effect on exercise-induced muscle gains.”
He adds, “it might give athletes looking to climb on the podium an edge but, even then, it’s doubtful.”
The best evidence shows that building muscle requires, along with resistance training, meeting daily protein and calorie requirements. If doing so means including a protein shake, that works. But don’t worry about downing it immediately after your workout.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD
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