Even the most casual exerciser knows that you need to eat food after you exercise – post-exercise nutrition helps with recovery and gaining muscle. It is often stated that you need to eat as soon as possible to maximize gains. Eating right after your work out is supposed to take advantage of the post-workout anabolic window or gains window. But… is there actually an anabolic window? The results from scientific investigations would argue no. That doesn’t mean that proper nutrition around your workout doesn’t give you a step up.
Getting Started
Before we get into the truth behind the post-workout anabolic window, we should define a few key concepts. I want to make sure these terms are highlighted because they will be mentioned throughout the article.
Muscle Protein Synthesis
Muscle protein synthesis is the process of building new proteins inside muscles.
Muscles are comprised of layers upon layers of proteins. Muscle protein synthesis is the process of ‘stacking’ new proteins on top of each other to build or repair muscle.
Amino acids (which we get by digesting food-based protein sources) are the building blocks of protein.
Protein synthesis is opposed by muscle proteolysis (breakdown).
The balance between muscle protein synthesis and muscle proteolysis is your net muscle protein balance. Net muscle protein balance determines if you gain or lose muscle mass (Atherton & Smith, 2012).
From now on, I’ll be calling muscle protein synthesis MPS.
Catabolic
Catabolism or a catabolic state is a general breakdown of large molecules to smaller molecules in the body. Catabolic states are when your metabolism is burning more than it is building.
We can think of this as taking apart a Lego building to use the pieces somewhere else. We are removing parts from a whole structure which then can be transported and used for something else or stored away.
Muscle proteolysis is a catabolic event because muscle protein is broken down into smaller component parts.
Anabolic
When someone says anabolic, we often think of anabolic steroids. That is also how I first learned to remember what anabolic and catabolic meant.
People use steroids to get bigger, so anabolic means building.
Anabolism is the process of constructing bigger molecules from smaller parts. MPS is an anabolic process.
Why We Need to Eat Protein for Muscular Gains
As mentioned above, MPS drives muscle building. We need the building blocks of protein to build muscle.
Amino acids are the building blocks of muscle protein, so we need to have amino acids available.
Research has shown that having ample amino acids available in the blood stream will spike MPS processes (Schoenfeld & Aragon, 2018a).
How do we get amino acids?
We can increase amino acids in the body by digesting protein – whether it be in the form of a shake or a chicken breast.
Breakdown of the protein we consume starts in the stomach. The process continues in the small intestine thanks for some enzymes from the pancreas. Eventually, the protein is broken down to single amino acids that move through the intestine wall into the blood stream (3).
Additionally, ingesting amino acids in a shake via branched-chain amino acid supplements will increase MPS.
Working Out, Fueling and Recovery
Research has repeatedly shown that training depletes stored fuel in the body. When we exercise we use stored glycogen (sugar) and amino acids to fuel the processes that allow us to work out (Aragon & Schoenfeld, 2013).
We need to replace the fuel stores that we burned in our workout. This is where post-workout nutrition becomes important.
Eating or drinking the right nutrients following exercise begins the rebuilding process of broken-down muscle tissue (Aragon & Schoenfeld, 2013). And as I’ve written about before, the body over-recovers or super-compensates during the rebuilding process. This allows the body to be stronger and better handle stress in the future.
Consuming the right mix of protein and carbs can increase MPS following exercise and decrease post-workout muscle breakdown. This combination can lead to greater muscle size and strength gains (Aragon & Schoenfeld, 2013).
What is the Anabolic Window?
The anabolic window is a supposed to be the period of time after a workout where the body is able to absorb a ton of nutrients and shift from catabolism to anabolism.
In the bro-science world it means that as soon as you finish your workout you should be downing a protein (with some carbs) shake to maximize gains.
In the scientific community, the anabolic window is termed the “nutrient timing theory”. The nutrient timing theory suggests “ingesting the proper nutrients less than 1 hour after the completion of an exercise bout promotes an additive anabolic response that maximizes hypertrophic adaptations” (Schoenfeld & Aragon, 2018b).
Proponents of the nutrient timing theory suggest that delaying protein intake (consuming it later than 1 hour post-exercise) could compromise muscular gains (Schoenfeld & Aragon, 2018b). However, consuming protein within the 1-hour window is supposed to maximize post-workout MPS.
Where did the Anabolic Window Come From?
The belief that there’s an anabolic window after exercise comes from a few studies in the 1990s. Those studies showed that there was increased MPS when amino acids were consumed immediately after working out versus delaying their ingestion (Schoenfeld & Aragon, 2018b).
These studies in the 90’s were based on long duration aerobic exercise in both human and canine subjects. Schoenfeld and Aragon provide some rebuttal on the conclusions in their paper on the subject.
However, these studies have been cited as the “reason” we need to consume protein right after workouts to maximize gains.
Is There ACTUALLY an Anabolic Window After Workouts?
Now that we know why the body needs protein and where the idea of the anabolic window comes from, the question is: is there actually an anabolic window?
On the surface level, there seems to be some scientific support for the post-exercise anabolic window theory.
In fact, short-term resistance training studies show a positive influence of eating within an hour of working out. It seems to lead to a bigger hypertrophy effect than not eating within an hour of your workout (Schoenfeld & Aragon, 2018b).
However, it has been shown that the majority of the studies that show a positive effect of nutrient timing can have their results explained by differences in total protein intake.
One such study provided 1.3 g/kg of protein to the group that didn’t eat within an hour of working out while providing 1.7 g/kg to the group that did eat following their workout. As you would expect, the group that was getting 1.7 g/kg of protein saw greater hypertrophy effects.
The recommended protein intake is between 1.6–2.2 g/kg (0.72-1 g/lb) per day for maximal muscular effects. Therefore, it makes sense that a group that was receiving less than the recommended amount of protein would see less improvement (Schoenfeld & Aragon, 2018b).
The Effect of Protein Before vs. After Workout on Strength
Recent work by Schoenfeld has concluded that there is NO DIFFERENCE between consuming protein before or after exercise when the amount of protein was matched between groups. They concluded that any benefit of post-workout nutrition in the “anabolic window” can be nullified if protein is consumed before the workout (Schoenfeld et al., 2017).
Candow et al. found that consuming 0.3g/kg (0.14 g/lb) before or after resistance training produced similar increases in 1RM leg press and bench press strength over a 12-week training study (Candow et al., 2006).
The combined results suggest there is no real difference between eating before or after their workout. You should pick one or the other based on your own personal preference, tolerance for training with food in your stomach, and time availability (Schoenfeld et al., 2017).
How Should You Plan Meals Around a Workout
At the end of the day, the total amount of protein you consume in a day is the most important component to increase exercise-induced muscle development (Schoenfeld & Aragon, 2018b). You should shoot for 1.6-2.2 g/kg (0.72-1 g/lb) of total protein in a day.
The research shows that if you hit those numbers, you should be (nearly) maximizing your muscle size and strength gains.
The research also suggests that the anabolic window is really a large window of time around your training. This includes 3+ hours both pre and post-training. If a meal with ample protein is consumed about 3-4 hours prior to your workout you do not need an immediate post-workout meal (Schoenfeld & Aragon, 2018b).
Minimal to moderate doses of high-quality protein consumed before training is probably enough to sustain amino acid delivery for MPS during the post-workout period. Eating a solid meal about 2 hours after exercise should be enough to maximize recovery and muscle building (Aragon & Schoenfeld, 2013).
Post-workout nutrition is only needed for those that train fasted, such as those that train prior to lunch or after a full day at work (Schoenfeld & Aragon, 2018b).
For these people, it is important to consume protein or amino acid supplements post-workout. About 25 g of protein as soon as possible is a good starting point to potentially increase muscle growth and recovery (Aragon & Schoenfeld, 2013).
- Read More: What Science Says About Over Training
- Read More: 9 Scientifically-Backed Tips to Gain Strength
References:
Aragon, A. A., & Schoenfeld, B. J. (2013). Nutrient timing revisited: Is there a post-exercise anabolic window?11.
Atherton, P. J., & Smith, K. (2012). Muscle protein synthesis in response to nutrition and exercise: Muscle protein synthesis in response to nutrition and exercise. The Journal of Physiology, 590(5), 1049–1057. https://doi.org/10.1113/jphysiol.2011.225003
Berg, J., Tymoczko, J., & Stryer, L. (2002). Section 23.1, Proteins Are Degraded to Amino Acids. In Biochemistry. 5th edition. W H Freeman. https://www.ncbi.nlm.nih.gov/books/NBK22600/
Candow, D. G., Chilibeck, P. D., Facci, M., Abeysekara, S., & Zello, G. A. (2006). Protein supplementation before and after resistance training in older men. European Journal of Applied Physiology, 97(5), 548–556. https://doi.org/10.1007/s00421-006-0223-8
Schoenfeld, B. J., & Aragon, A. A. (2018a). How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Journal of the International Society of Sports Nutrition, 15(1), 10. https://doi.org/10.1186/s12970-018-0215-1
Schoenfeld, B. J., & Aragon, A. A. (2018b). Is There a Postworkout Anabolic Window of Opportunity for Nutrient Consumption? Clearing up Controversies. Journal of Orthopaedic & Sports Physical Therapy, 48(12), 911–914. https://doi.org/10.2519/jospt.2018.0615
Schoenfeld, B. J., Aragon, A., Wilborn, C., Urbina, S. L., Hayward, S. E., & Krieger, J. (2017). Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ, 5, e2825. https://doi.org/10.7717/peerj.2825