One of the most common worries of gym goers is that of protein intake and getting protein in as soon as possible after exercise.
There is a deep belief that rapid intake, directly after exercise is essential to maximize growth and gains, but is protein intake as time-sensitive as people think? Let’s dive in and see, shall we?!
Why is protein important for gaining muscle mass?
Proteins are made up of amino acids and proteins provide structure to all cells in the human body. Protein is essential for growth and repair of tissue. Our muscles (along with many other structures) are composed mainly of proteins and when protein in the diet is insufficient and training stimulus is low, these tissues begin to break down, getting smaller and smaller in a process termed atrophy.
The opposite is also true, when an appropriate long-term training stimulus in imposed alongside a suitable dietary approach (with respect to total, timing, and type), muscle growth (hypertrophy) occurs.
The proteins in our body are in constant state of turnover, with proteins being created and broken down continually throughout the day. When we eat, synthesis spikes, as we fast, it decreases. Amino acids are constantly being incorporated into new proteins (creation) and proteins constantly being broken down into amino acids. For muscles to grow and repair, like energy balance, protein creation must be greater than breakdown.
Muscle protein synthesis is the metabolic process that describes the incorporation of amino acids into bound skeletal muscle proteins.
The turnover of structural proteins (contractile proteins, collagen) is relatively slow when compared to other proteins like enzymes. But after resistance training, this turnover increases due to an acceleration of the rates of protein synthesis and breakdown. Research in the late 1990s by Biolo et al., (1995;1007) found that the increase in muscle protein synthesis can be 2.5 times greater than breakdown after resistance training and/or protein feeding.
What happens to protein turnover after training?
There is an increase in muscle protein breakdown after exercise due to the stress imposed on the muscles but when protein intake is sufficient, the rate of breakdown remains lower than synthesis, meaning that repair and growth can occur. When protein intake is low and amino acid availability is low, then the rate of synthesis is lower, and a net breakdown can occur.
As noted earlier, when we eat, there is a spike in protein synthesis. There is an additional spike in synthesis after resistance training. When you combine both feeding and training, there is an elevation of muscle protein synthesis above normal ranges. It would seem plausible then to get protein in directly after training to maximize this anabolic potential.
- The heightened protein turnover after exercise is not a short lived one, the elevations in protein synthesis and breakdown are still present 3 to 24 hours post training, showing a transient decline over time. This is the first hint that immediate protein intake is NOT essential. Waiting a few hours won’t matter a whole pile but the longer you do wait, the lower the synthetic response.
- Secondly, when a person becomes more trained, they become more efficient meaning the rate of protein turnover decreases. The impact of this is that the same training stimulus will be less potent in promoting growth as the rate of breakdown and synthesis are lower. Now the nuances become apparent. This is one of the exact reasons why novice lifter has such rapid gains while experienced lifters make minute gains over the long-term. It also highlights the need to progress training over time.
- Thirdly, the protein bolus and the type of protein has an impact on the muscle protein synthetic response. If the dose of essential amino acids is lower and if the total protein content is lower, then the synthetic response is not seen as being less responsive.
- Additionally, the protein kinetics in terms of digestibility and absorption play a role, for example the difference between whey and casein on muscle protein synthesis. If you consume casein, the rate of digestion and absorption is slower, resulting in a slower, more sustained aminoacidemia, whereas with whey, this occurs much quicker with a faster rate.
What about training?
For growth to occur, the resistance training stimulus must first be appropriate. A well-executed training program should sufficiently stimulate synthesis of myofibril proteins and it is the imbalance between myofibril protein synthesis and breakdown that will determine muscle growth (hypertrophy).
Detailing a well-executed training program is beyond the scope of this article but variables such as load, reps, sets, tempos, fatigue and exercise set-up are crucial in creating an environment appropriate for growth.
If training is looked after, then the dietary approach will determine to a large extent the morphological change that will occur. Of course, there are other factors that are at play, but the two major variables are training and nutrition.
It is the long-term, repeated spiking of protein synthesis, by way of resistance training combined with appropriate nutrition that leads to hypertrophy.
In the hours after resistance training, as noted earlier, protein synthesis can be elevated above normal but only when protein feeding occurs. This heightened ability to increase protein synthesis lasts up to 24 hours and has a transient decline up to 48 hours.
There is no need to focus on getting protein in immediately. While it is important post-exercise, waiting an hour or two will make little to no difference. The most important thing is ensuring adequate total protein intake across the day and repeated stimulation of muscle protein synthesis from feeding.
After feeding there is a post-prandial decrease in muscle protein synthesis that last somewhere between 1 and 4 hours, suggesting that protein intake distribution is very important. You do not want to allow an excessively long period of time between feedings as the rate of breakdown will increase over time. The distribution of eating episodes of protein, day in day out, is vital. Each protein intake must be large enough to create a large amino acid delivery to maximally stimulate protein synthesis. The amount of protein required is dependent on the individual and not a blanket amount of protein for each person. Using exact gram recommendations is not a wise move.
It was previously thought that 20g of protein was adequate for all persons, but this evidence has since been shown to not represent all populations as there is an age-related decline in the protein synthetic response meaning that older individuals require more protein to maximally stimulate protein synthesis. Research has since agreed that a protein bolus of between 0.4 grams per kg of body mass is enough to stimulate protein synthesis. All of this talk of protein can at times, pull awareness away from the most important pillar of growth. Total energy intake.
Growth will likely not occur in trained individuals who do not consume adequate energy. While protein is of course important, if you are a trained individual looking to grow, you need to let go of ego and accept that for real growth and progress to occur, getting a bit fluffy for a few months is needed. Muscle growth is a slow process and time needs to be respected. Ditch the mindset that protein directly after exercise is the solitary factor required for muscle growth. Instead make an effort to improve total daily protein intake and distribution, and then once these two aspects are squared away, come back to the pre- and post- workout feeding.