Does Protein Timing Matter For Muscle Building?
This Week’s Research Highlight
Background
If you are trying to get stronger and/or build muscle, you primarily need to do two things.
First and foremost, you need to engage in some form of resistance training. This is by far the most critical variable, of course.
But we also know that you need an adequate dose of dietary protein. When you consume protein, it is broken down into its constituent amino acids, which are then used to repair the damaged muscle fibers, and remodel those strands to make them more durable than before. Accordingly, dozens of randomized trials have demonstrated that supplementation with protein improves lean mass gain in people who participate in a strength training program.
However, there has been a simmering debate, going back many years, regarding the ideal timing of protein consumption to maximize these adaptations. How should protein intake be distributed across the day? And when should protein be consumed in relation to resistance training? Does it even matter?
For quite a while, we’ve thought that protein timing is likely to be pretty important, due to a hypothesized phenomenon known as the anabolic window. The idea here is that there is a short period of time right after training when your muscles are repairing themselves and are more receptive to taking up amino acids. Thus, if you consume protein within an hour after your workout, your recovery will ostensibly be greater and you’ll reap more gains, versus if you had waited till later.
Now, a number of studies have tried to explore the practical impact of protein timing. The problem is that many of these trials fail to control for total protein intake in both control and experimental groups.
Here's a good example of what I'm talking about. One study took a group of young men and assigned them to either drink a very high protein dairy-based shake or a placebo maltodextrin shake immediately post-workout. The dairy group experienced significantly greater increases in muscle mass and strength performance than the placebo group.
This, at first glance, certainly appears to support the concept of the anabolic window. Except for one thing.
As you can see from the table above, the addition of the protein shake meant the experimental group was consuming way more total protein every day during the study period, compared to the placebo group. During their study, their protein daily intake increased by around 66 grams, while the protein intake for the placebo group stayed at baseline levels.
So were their strength and muscle gains specifically attributable to the high-protein shake post-workout, or was it because they were just getting a whole lot more protein overall, regardless of when it was being consumed?
A better test for whether or not protein timing per se matters would be to take two groups and ensure that their total 24-hour protein intake is similar, but only manipulate the timing of that intake. For instance, you could have one group consume a significant portion of their protein around their training bouts, while the other group waits a few hours.
Fortunately, a team of researchers recently did just that.
Let's take a look at what they found.
Study Design
Researchers recruited 31 young men who were already experienced in strength training. For eight weeks, all participants participated in a standardized resistance training program supervised by a certified trainer, while consuming a very high protein diet (2 grams of protein per kilogram of body weight).
To put that into practical terms, that meant that their daily protein intake, on average, was increasing from around 85-95 grams all the way up to 160 grams per day on average. If you’ve ever tracked food before, you know this is not an easy target for most folks to reach!
In order to ensure that subjects met this protein goal, the men logged their nutrition intake daily through a mobile app and they consulted with a registered dietitian every week during the study.
The men were randomly divided into two groups, and this where study conditions diverge.
One group of men was assigned to consume 25 grams of supplemental protein (whey protein isolate) immediately prior to training and another 25 grams immediately post-workout.
The other group took in 25 grams of supplemental protein three hours before training, and 25 grams of protein three hours after their exercise session.
Okay, so both groups were consuming the same dose of protein every day for eight weeks, and they were all regularly taking in 50 grams of supplemental protein in the form of whey isolate. Only the timing of protein intake was altered, so that one group was consuming 50 grams of protein within the "anabolic window," and one group was taking in 50 grams of protein three hours apart from their training session.
To determine how the dietary regimen was affecting these participants, the researchers assessed body composition (most importantly muscle mass) via multifrequency bioelectrical impedance, and they measured strength gains through leg press, chest press, and inverted row exercises, as well as vertical jump height.
Findings
After eight weeks, both groups showed significant increases in muscle mass, which was accompanied by improved performance in all of the tested strength exercises.
However, there were no differences between the two groups. In other words, whether the men consumed protein immediately before/after or three hours before/after training did not affect either muscle or strength gains.
The fact that precise protein timing didn’t seem to matter here honestly isn’t that surprising. As you might recall, a groundbreaking study, which we discussed in a newsletter earlier this year, showed that the rate of muscle protein synthesis in response to a large protein bolus was elevated 12 hours after consumption. And prior research has shown that resistance exercise renders skeletal muscle more sensitive to amino acids for up to 24 hours after the training bout. (Good news for those of you who do intermittent fasting!)
However, you do still need to make sure that you’re getting enough protein. And that should be another key takeaway here.
Recall that these men had already been training for a few years, so you would expect it to be relatively hard to elicit new muscle growth, compared to a newbie. They also hadn’t been on a particularly low protein diet — prior to the study, they had been consuming 1-1.2 grams of protein per kilogram of body weight, which is close to the average intake for American adults. Yet, in just two months, they were able to see significant gains in lean mass (more than two pounds) as well as quantifiable strength improvements after boosting their daily protein intake.
So, if you want to maximize your gains, you need to shoot for a daily protein target that is well above the current RDA (0.8 grams per kilogram). In fact, research indicates that people may see benefits at up to double the RDA, around 1.6 grams of protein per kilogram of body weight, which basically lines up with this study.
Random Trivia & Weird News
When we lose weight, most of the burned fat actually leaves the body through our breath.
A survey of physicians, dietitians, and personal trainers found that most believe that fat is converted to energy or heat when it is lost. This is not correct, and indeed would be a violation of the law of conservation of mass. But where exactly does it go?
In order to answer this question, you must first consider what is happening when you lose body fat. Stored triglycerides are made of oxygen, hydrogen, and carbon.
When triglycerides undergo oxidation, these atoms are broken apart, generating around 16% H2O (water) and 85% CO2. The water is excreted through urine, sweat, and other bodily fluids. Meanwhile, the carbon dioxide leaves the body via the lungs, through exhalation.
Random Trivia & Weird News
- David Allison: Rethinking nutrition science: the evolving landscape of obesity treatment, GLP-1 agonists, protein, and the need for higher research standards. Via The Peter Attia Drive.
- Scott Young: Evidence-based strategies for learning & skill acquisition. Via Sigma Nutrition Radio.
Products We Like
Chobani Complete
If you’re looking for an easy way to get more protein in your diet, look for these in the refrigerated section of the grocery store. They contain 20 grams of high-quality protein, 3 grams of soluble fiber, and 320 mg of calcium (25% of the Recommended Daily Value). The product also comes in a bunch of tasty flavors — I’m partial to the cherry vanilla myself.
humanOS Catalog Feature of the Week
The FLASH Diet
We’d like to highlight a course from the Ideal Weight Program, developed by Stephan Guyenet, a researcher who specializes in the neuroscience of eating behavior and obesity.
The Ideal Weight Program is an evidence-based system for sustainable weight management which teaches you the science of body weight regulation and eating behavior, and translates it into simple, practical strategies for weight management. This program offers three different diets based on your weight management goal. For those who need to lose body fat relatively rapidly (but safely), the FLASH Diet is the plan for you. Importantly, protein is a key element of this approach.
FLASH stands for Fat Loss and Sustainable Health, and is modeled after protein-sparing modified fast diets that were developed by researchers in the 1970s and remain the most effective fat loss plan ever studied. In this course, Stephan explains the background behind FLASH diet, where it fits in the sequence of the Ideal Weight Program, what to eat and how to prepare food to adhere to this plan, and more.
Wishing you the best,
