It’s the last set of your training session.
You push hard as you grind out the last couple reps.
You hastily re-rack the weight and make a mad dash toward the locker room to get your shaker cup filled with protein.
Precious seconds tick off the clock as you race against time trying to get some protein in your system. As you open the locker and rifle through your bag, you realize you forgot your protein at home.
“NOOOOOOO!!!!”, you scream as you look to the sky.
Your workout was completely wasted because everybody knows that if you don’t get protein in immediately after training then it was all for nothing.
This is a scenario that is played out at gyms across the country. Gym goers sprinting for their protein as soon as their training session ends for fear of losing all their gains if they don’t.
Does it really need to be this dramatic? Does post-training nutrition really matter as much as we’ve all been told?
Let’s take a look at what the science actually says about it.
What follows are some post-workout myths, claims that are commonly made by people who believe the myths, and scientific evidence for or against the claims.
Myth 1: Your post-workout meal should consist of protein and carbohydrates.
Theory: Protein is needed to decrease muscle protein breakdown (wasting) and increase muscle protein synthesis (building). Carbohydrates are needed to replenish glycogen stores.
Scientific evidence: To understand the science behind post-workout nutrition we must first understand that muscle hypertrophy is the result of positive protein balance. Positive protein balance is achieved when muscle protein synthesis exceeds muscle protein breakdown.
Protein synthesis is the process by which muscles are built. Ingesting protein decreases muscle protein breakdown and increases muscle protein synthesis. Consuming protein before and after workouts has also been shown to increase muscle fiber size and muscle strength 4. This tells us that ingesting protein after training is probably a good idea. But what about carbohydrates?
It turns out that the effect of insulin on muscle protein synthesis is actually not additive to the effect of protein on muscle protein synthesis or muscle protein breakdown1. Carbohydrates are thus not necessary post-workout if the amount of protein consumed is enough to maximally stimulate rates of muscle protein synthesis1.
So how much protein is “enough”? The ideal amount of protein post-workout appears to be 20-25g1, 2,3, and 9g of essential amino acids has been found to accomplish the same result3.
So why do we always hear about pairing carbohydrates with our post-workout protein shakes? The human body will replenish glycogen stores on its own without an immediate source of carbohydrates post-workout. However, consumption of carbohydrates after a workout can help speed up this process.
For athletes who are training multiple times per day or who engage in long, strenuous aerobic activity, carbohydrates post-workout can be very beneficial3, but consumption of carbohydrates after resistance training is typically not necessary. Your body will replenish glycogen stores just fine before your next training session if you only train once a day.
Myth 2: Whey protein isolate is the most important post-workout supplement.
Theory: Whey protein is quickly digested and will impact on muscles quickly, increase muscle protein synthesis, and maximize muscle hypertrophy.
Scientific evidence: Essential amino acids and intact protein have both been shown to maximally increase rates of muscle protein synthesis3, while protein hydrolysate, e.g. hydrolyzed whey, increases rates of protein digestion and absorption5.
Protein hydrolysates are formed by splitting proteins into a resulting mixture of amino acids, whereas other protein powders, regardless of whether or not they are isolates (i.e. 90% or higher protein content), consist of larger peptide structures. A protein hydrolysate is therefore the desired supplement if you are concerned with rapid digestion and absorption.
In contrast, leucine, a specific amino acid, has been shown to be critically important for reaching maximum protein synthesis. It has been shown that 3-4g of leucine is the ideal quantity for optimizing muscle protein synthesis6. If leucine is consumed without other amino acids, a carbohydrate source will help increase rates of muscle protein synthesis5.
However, the effect of carbohydrates on muscle protein synthesis is not additive to the effects of at least 20g protein or 9g essential amino acids, as mentioned earlier.
Myth 3: Post-workout nutrition depends on factors like body type and gender.
Theory: Everyone is different. For instance, a female looking to add muscle doesn’t have the same needs as a male with the same goal.
Scientific evidence: Post-workout nutrition recommendations may depend on type and frequency of exercise but not on body type and gender. Moreover, regardless of your overall intake, there is no real benefit to consuming a large amount of carbohydrates with your postworkout meal.
In other words, a male or someone with a higher body weight might require a greater caloric intake than a female or someone with a lower body weight, but this requirement doesn’t necessarily translate to post-workout needs.
One study showed no difference in anabolic response following consumption of 30g or 90g of carbohydrates in addition to essential amino acids; both amounts significantly decreased muscle protein breakdown and increased muscle protein synthesis7.
As long as insulin is in the normal physiological range, i.e. not deficient or in excess, there is a lack of evidence showing any benefit to a huge insulin spike as compared to a moderate rise7. Based on existing research, anyone with similar workout regimens and goals should be fine adhering to similar post-workout nutrition guidelines.
Myth 4: Your post-workout meal should be consumed immediately after your workout.
Theory: Your body needs an immediate supply of calories post-workout to be digested and absorbed to optimize protein synthesis.
Scientific evidence: As alluded to earlier, post-workout, your body will be in a catabolic state. The ideal post-workout routine will therefore promote anabolism via protein intake.
Carbohydrates alone will not promote anabolism. Ingestion of protein will increase rates of muscle protein synthesis post-workout, while consumption of a balanced meal may be more beneficial after at least an hour post-workout.
According to one study, muscle protein synthesis was significantly increased when an amino acid carbohydrate drink compared to a placebo was taken 1 hour or 3 hours after resistance training8. However, there is a lack of evidence indicating whether this advantage is maintained over a 24-hour window.
The increase in muscle protein synthesis could be due to consuming calories in general and not necessarily consuming calories 1-3 hours after a workout.
The importance of the post-workout meal should not be overestimated. Additionally, net muscle protein synthesis has been shown to increase to a significantly greater extent when essential amino acids and carbohydrates are consumed before resistance training than after9, and total protein intake has been shown to be a stronger predictor of muscle hypertrophy than post-workout intake10.
This suggests that not only your pre-workout meal but also your total daily protein intake has a greater effect on muscle protein synthesis than the post-workout meal.
Applying the Evidence
Drinking a post-workout protein shake offers potential benefits without potential detriments, so if you want to build muscle and/or strength, it’s a good idea to grab some protein post-workout.
Consumption of carbohydrates immediately post-workout does not add to the benefits of consuming protein immediately post-workout, so aside from protein, post-workout nutrition is really more about preference than progress. If you’re famished after a workout, eat.
If you forgot your protein shake, don’t stress. There are many other hours in the day when you can get the calories you need to recover.
- Staples AW, Burd NA, West DW, Currie KD, Atherton PJ, Moore DR, Rennie MJ, Macdonald MJ, Baker SK, Phillips SM. Carbohydrate does not augment exercise-induced protein accretion versus protein alone. Med Sci Sports Exerc. 2011 Jul;43(7):1154-61.
- Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, Prior T, Tarnopolsky MA, Phillips SM. Ingested protein dose reponse of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009 Jan;89(1):161-8.
- Beelen M, Burke LM, Gibala MJ, van Loon L JC. Nutritional strategies to promote postexercise recovery. Int K Sport Nutr Exerc Metab. 2010 Dec;20(6):515-32.
- Andersen LL, Tufekovic G, Zebis MK, Crameri RM, Verlaan G, Kjaer M, Suetta C, Magnusson P, Aagaard P. The effect of resistance training combined with timed ingestion of protein on muscle fiber size and muscle strength. Metabolism. 2005 Feb;54(2):151-6.
- Koopman R, Crombach N, Gijsen AP, Walrand S, Fauquant J, Kies AK, Lemosquet S, Saris WH, Boirie Y, van Loon LJ. Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein. Am J Clin Nutr. 2009 Jul;90(1):106-15.
- Stark M, Lukaszuk J, Prawitz A, Salacinski A. Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training. J Int Soc Sports Nutr. 2012 Dec 14;9(1):54.
- Glynn EL, Fry CS, Drummond MJ, Dreyer HC, Dhahani S, Volpi E, Rasmussen BB. Muscle protein breakdown has a minor role in the protein anabolic response to essential amino acid and carbohydrate intake following resistance exercise. Am J Physiol Regul Integr Comp Physiol. 2010 Aug;299(2):R533-R540.
- Rasmussen BB, Tipton KD, Miller SL, Wolf SE, Wolfe RR. An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise. J Appl Physiol (1985). 2000 Feb;88(2);386-92.
- Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206.
- Schoenfeld BJ, Aragon AA, Krieger JW. The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr. 2013 Dec;10(1):53.