By Eirik Garnas
Everyone who’s been lifting weights for some time have inevitably heard – and most likely bought into – a lot of the gym talk and magazine wisdom surrounding training and diet. Besides learning that eating every other hour and completely destroying each muscle group once a week is the optimal way to go for muscle growth, new strength trainees usually hear about the “anabolic window” that opens up after a workout and the boost in protein synthesis and muscle growth that occur if you consume fast-absorbable protein directly after your last set. It doesn’t matter whether you’re hungry or not, just getting it down is the priority. While some trainees cling on to these notions for their entire lifting career, those who start reading research and evidence-based information quickly learn that a lot of the general beliefs about training and nutrition are either inaccurate or outright harmful. But, while a lot of the myths in the fitness community are quickly dismissed by these smart lifters, the majority still hold onto their post-workout protein shake. Getting enough protein into your body is clearly essential if you want to maximize muscle growth and strength gains, but does it really make a difference whether you get some of these essential building blocks into your body directly after training or not?
“Listen to your body”. This short phrase is often considered the first rule of training, nutrition, and health since it doesn’t really matter what researchers, coaches, and experienced athletes say is optimal if it’s not compatible with your body. Most trainees learn how to adjust their diet and training program in accordance with their recovery rate and progress, but for some reason the pre- and post-workout food intake is often set in stone.
But how did the ideas about pre- and post-workout protein consumption get so ingrained in the fitness community? Bodybuilders selling and using supplements and ads in fitness magazines and websites certainly have a significant impact, but that’s not all. Most of us have probably heard or read about the scientifically proven effects of consuming fast-absorbable protein or branched-chain amino acids within about 30 minutes after training, and on a superficial level it does seem to make sense that consuming protein in and around a training session could help you build more muscle and strength.
Enter protein timing
Protein timing involves the consumption of protein in and around an exercise session, and proponents of this nutritional strategy claim that this type of nutrient timing enhances strength- and hypertrophy-related adaptations.
Let’s do a quick example to illustrate the idea behind protein timing. Adam has been lifting weights for 5 years and gained a respectable amount of muscle. He typically consumes a large mixed meal 2 hours prior to his strength training sessions and then another meal 1-2 hours after his workout. In total, he eats 4-5 meals a day, and since he’s dead set on increasing his strength and building muscle, he’s consuming plenty of animal source foods. Adam doesn’t use a lot of supplements, but one of his meals of the day includes a protein shake. His average daily protein intake is 180 grams (~2 g/kg/day).
If protein timing does enhance muscle growth and strength development, Adam should see even greater progress by drinking the protein shake immediately before or after his workout! However, it’s important to note that to adequately determine the effects of pre- and post-workout protein consumption, his total energy and protein intake have to stay the same.
Protein timing (in and around a workout) doesn’t have a significant impact on muscle growth and strength development
Studies on protein timing show mixed results (1,2,3,4). It’s therefore easy for supplements manufacturer and people with a strong opinion on the matter to cherry pick a study that seems to support their position on protein consumption pre- and/or post-workout, but if we take a closer look at most of these chronic training studies there are several methodological shortcomings that limit their usefulness. Perhaps the greatest issue with a lot of the studies on protein timing is that participants who consume protein directly before and/or after their workouts often have a higher total protein intake than subjects who’re not. Since a higher protein intake is associated with increased hypertrophy (up to a certain point), this unmatched protein consumption in the treatment and control group will have a significant impact on the results. To illustrate this, let’s go back to the example with Adam and adjust his protein intake so he’s only consuming 1,4 g/kg/day of protein each day. His daily protein intake is now below what is considered optimal in terms of maximizing increases in muscle mass, and it’s therefore no surprise that adding additional protein in and around his training sessions will make him gain more muscle.
Last year, Alan Aragon, Brad Schoenfeld, and James Krieger were the first to investigate the effects of protein timing on hypertrophy and muscle strength in a meta-analysis. After contrasting and combining results from several randomized controlled trials, the authors concluded the following: “In conclusion, current evidence does not appear to support the claim that immediate (≤ 1 hour) consumption of protein pre- and/or post-workout significantly enhances strength- or hypertrophic-related adaptations to resistance exercise. The results of this meta-analysis indicate that if a peri-workout anabolic window of opportunity does in fact exist, the window for protein consumption would appear to be greater than one-hour before and after a resistance training session …” (5).
The authors also note that the positive effects associated with protein timing seem to stem from a higher total protein intake in the treatment groups than in the control groups, but that more matched studies – especially in well-trained individuals – are needed to draw firm conclusions.
Overall it’s safe to say that total protein intake is far more important than protein timing when it comes to muscle and strength gains, and as long as you eat enough protein throughout the day to meet your requirements, it doesn’t seem to matter much whether some of this protein is consumed immediately before and/or after your workout or not. However, it’s important to note that these studies focus on protein intake in and around a training session, not the optimal frequency of protein-rich meals throughout the day.
But what if you combine protein with carbohydrates, does that make a difference? Most lifters typically include fruits, rice cakes, or carbohydrate supplements in their post-workout meal in an attempt to restore glycogen stores and increase protein synthesis, but the fact is that recent studies indicate that a greater insulin response following the post-workout meal doesn’t contribute to muscle protein anabolism in young adults (6). This can help explain why adding carbohydrate to a protein-rich post-workout meal doesn’t seem to enhance post-exercise muscle protein synthesis (7,8,9).
There are two primary reasons why consuming fast-absorbable protein and carbohydrates directly after a strength training session isn’t really a top priority for the average lifter (given that he gets enough protein during the day to meet his requirements and doesn’t delay his first post-workout meal for too long). First of all, the science doesn’t really show that consuming carbohydrate and/or protein directly after a workout enhances muscle growth or strength development. Second, if you’ve eaten a mixed meal 2-3 hours prior to training (like most serious lifters do), you’ve already supplied a generous dose of nutrients that are being broken down, absorbed, and metabolized both during and after your workout.
Should you include protein powders in your diet?
Since a post-workout protein shake doesn’t really seem to boost muscle growth or strength gains, you might be asking whether you will benefit from including protein shakes in your diet at all. While the answer to this question primarily depends on your ability to get enough protein from “real food”, there are also other considerations you should have in mind. Let’s briefly look at some of the pros and cons associated with the consumption with protein powders, with an emphasis on whey protein.
- Protein powders help increase your total daily protein intake
Protein shakes are clearly a convenient and cheap way of increasing the total daily protein intake, and many serious strength trainees find that they aren’t able to get enough high-quality protein into their diet without supplementing. Since sources of protein such as free-range eggs, grass-fed meats, and seafood are more expensive and require more preparation than sources of fat and carbohydrate, protein is often diluted in favor of carbohydrate and fat, and consuming protein powders after a training session or during the day can therefore be an efficient way of increasing the total protein intake. This can be especially beneficial for strength trainees who pay little attention to their overall diet and protein consumption. “High-protein” diets are often associated with bodybuilding and strength training, but are also very effective for weight loss.
- Protein powders can help speed up the recovery process
Although protein timing doesn’t seem to offer any substantial benefits in terms of hypertrophy and strength, nutrient timing does affect your recovery rate and is therefore of special concern to those who perform several workouts during the same day. In general, if you’ve just finished a brutal workout and feel the need for some fast-absorbable energy, it’s probably a good idea to get some food into the system within a relatively short timeframe to kick-start the recovery process. However, there isn’t any reason to force 2 scoops of whey protein down if you’ve eaten a large mixed meal prior to training and aren’t really that hungry directly after your workout.
- There are many health benefits associated with the consumption of protein powders
Besides the convenience of including protein shakes in the diet in the context of boosting protein intake and recovery, protein powders are also considered functional foods that have positive effects on health beyond basic nutrition. Most of the research has focused on the bioactive compounds and nutrient value of whey protein, which increases the antioxidant enzyme Glutathione (10) and is an abundant source of Branched-Chain Amino Acids (BCAAs). Whey protein has been shown to possess antioxidant-, antihypertensive-, antitumor-, hypolipidemic-, antiviral-, antibacterial-, and chelating- properties, which probably stem from the conversion of the amino acid cysteine to glutathione (11). Also, certain components in whey, such as lactoferrin and immunogolublins, have immune-enhancing effects (12), and several studies support a role for whey protein in the prevention and treatment of metabolic diseases (13).
- In evolutionary terms, the consumption of a highly concentrated source of protein is a novel behaviour
Protein powders contain a higher concentration of protein than anything we’ve been eating throughout most of our evolution, but it’s unclear whether this unnatural macronutrient composition poses a problem or not. The evolutionary argument isn’t especially conclusive in terms of protein timing as our hunter-gatherer ancestors didn’t really train like bodybuilders or weight lifters. Also, they didn’t necessarily do what was optimal in terms of recovery and muscle growth. However, looking at the human diet in an evolutionary perspective can help us understand what types of foods we’re naturally adapted to eat. While we don’t need to eat like our paleolithic ancestors (or have access to the same food) to be healthy, we can learn a lot by studying the mismatch between modern sources of food and those we’ve been eating throughout most of our evolution. Both highly dense sources of carbohydrates (e.g., refined grain products, sugar) and fat (e.g., high-fat cream, vegetable oils) are recent introductions in the human diet and because of their unnatural macronutrient composition these products can potentially induce a state of chronic low-grade inflammation by promoting the absorption of endotoxins into systemic circulation. Highly dense sources of protein such as protein powders are also a very recent introduction in the human diet, and although there is currently little evidence showing that protein powders are harmful to ones health, we can’t exclude the possibility that dense sources of protein could have some potential adverse effects that haven’t yet been fully investigated.
- Consumption of whey protein can increase acne severity
Besides the insulinogenic effect of whey protein, some of the hormones that are present in milk are also present in whey, and this could help explain why whey proteins seem to increase acne severity in some people (14,15,16).
- What about the insulin spike?
Whey protein has a very powerful effect on insulin secretion, and although insulin sensitivity is heightened after a training session, there are few (if any) studies showing that a similar amount of protein from whey is superior to meat, eggs, and seafood after a workout. Is the potent effect on insulin secretion following consumption of whey protein beneficial, benign, or bad? We can’t say for sure at this point. Recent research questions the notion that a greater insulin response post-workout contributes to muscle protein anabolism (17), and I’m personally sceptical to the idea that a post-workout insulin spike is something to aim for. This is also supported by recent literature which shows that a post-workout protein shake, with or without added carbohydrate, doesn’t seem to enhance muscle growth or strength development. However, if you’re a big fan of protein timing it’s clearly more convenient to bring a shake than chicken and fruit to the gym.
- A lot of protein powders on the market are of poor quality
Since the supplement industry is poorly controlled, a lot of protein powders contain metals and ingredients that lack safety data (18), and it can often be difficult to know whether you’re buying a high-quality supplement or not.
- Allergy and intolerance
While not really a downside of protein powders themselves, it’s worth mentioning that some people experience gas, bloating, or other problems following the consumption of protein powders because they are allergic to some of the protein fractions or don’t produce the necessary enzymes to break down all of the ingredients in the supplement.
In conclusion, total protein intake matters a lot more than protein timing (in and around a workout). The “anabolic window” doesn’t close 30 minutes after a workout, and there’s no reason to force down protein shakes or food until you’re actually hungry. There are several considerations you should keep in mind when deciding whether you need protein powders in your diet, chief of which is whether you’re able to get enough protein from food.
About the author
Name: Eirik Garnas
Besides studying for a degree in Public Nutrition, I’ve spent the last couple of years coaching people on their way to a healthier body and better physique. I’m educated as a personal trainer from the Norwegian School of Sport Sciences and also have additional courses in sales/coaching, kettlebells, body analysis, and functional rehabilitation. Subscribe to my website and follow my facebook page if you want to read more of my articles on fitness, nutrition, and health.