If there is one thing I’ve tried to make very clear the last couple of months it’s that maximizing protein synthesis is very important. It’s one of the most important factors when it comes to building muscle. To gain muscle, protein synthesis must be greater than protein breakdown. If there is no protein synthesis there is no muscle. The more you can tip the scales in favor of protein synthesis over protein breakdown the better off you will be. So with that comes a follow-up to an article I did a few months ago called Meal Frequency For Maximum Protein Synthesis.
I’m not here to change my opinion on the matter (though I always reserve the right to do so as I discover research or new research becomes available) but I have found some research that can be applied to the same information presented to potentially help increase protein synthesis even longer. I don’t know about you, but any time I find information that can help build more muscle, I get excited.
As a brief recap to the article I referenced research shows protein synthesis will increase after a meal containing protein but returns to baseline after about 3 hours even if blood amino-acid levels remain elevated. With that in mind the recommendation was to eat every 4-6 hours while eating enough protein to have at least 3 grams of leucine from whichever source of protein you are eating at each sitting. This will ensure you are elevating protein synthesis with every meal and maximizing the amount of protein to be used for protein synthesis each time. For a clearer understanding I do recommend reading the article in full if you haven’t done so already.
While this information still remains relevant, what I want to talk about today is the possibility of extending the time of protein synthesis beyond the typical 3 hours. Research by Wilson et al, (2011) (1) looked at supplementing with carbohydrates and/or leucine between meals with the goal of extending the period of muscle-protein synthesis in rats. They made sure the rats fasted for 12 hours and then gave them 20% whey protein. After 2 hours and 15 minutes they gave them either carbs, leucine or both, plus a group that only received water. What the results showed was the rats that got either carbs and/or leucine showed an extension of muscle-protein synthesis beyond 3 hours whereas the group who had water only had protein synthesis stop at the typical 3 hour mark.
The researchers believe it has something to do with the relationship between adenosine monophosphate-activated protein kinase (AMPK) and mTOR. mTOR is the main promoter of muscle-protein synthesis while AMPK, which is primarily catabolic, is an energy sensor. It is believed when protein synthesis is elevated it drops energy levels which when they drop far enough, which appears to be after roughly 3 hours, it signals a release of AMPK to provide energy, which in turn takes over mTOR and stops protein synthesis. When the carbs or leucine were administered, it was able to stop the signaling of AMPK and thus allowing protein synthesis to remain elevated for a longer period.
This information makes it entirely possible it’s not that your muscles become unresponsive to amino-acids but rather the body’s need for energy and the dominance of AMPK that determine how long muscle-protein synthesis will last. It then makes sense that carbs or leucine would help continue the elevation of protein synthesis because they are both readily available sources of energy, diminishing the need for AMPK to take over.
I realize this study is done on rats and not humans but before you discredit the research realize the mechanisms involved for protein synthesis in rats and humans are very similar. Granted I would love to see a follow-up study with humans to give us better answers, but for now this is all we have and it’s definitely worth paying attention to. Personally I think this research is fascinating and something I will be incorporating into my own diet routine. If you wish to give it a shot, whether you do carbs, leucine or both is up to you and largely depends on what fits your daily calorie and macronutrient requirements. If you do take leucine be sure to take a full BCAA supplement that also has isoleucine and valine at a 2:1:1 ratio. If you take leucine alone you will deplete your body’s sources of isoleucine and valine.
There are many methods to building muscle and many diet plans that work for different people. However, just because someone gets results doesn’t mean what they are doing is optimal. It’s entirely possible you could have better results with a more optimal plan. In my opinion there is nothing more optimal than spiking protein synthesis as many times as possible. Sure there are plenty of people who have success doing something like intermittent fasting, but if you can only spike protein synthesis every 4-6 hours and you are only eating in an 8 hour window, you are only allowing a chance for it to spike two or three times at best per day. There are even people who have success on the warrior diet, only eating once per day. To that I say good for them, do what works for you, but I’m not so sure that’s really the most optimal way to gain muscle. If a plan works for you and you like it, there is no need to change. What I’m here to do, however, is keep looking for the best possible ways to build muscle. Currently eating every 4-6 hours while taking in carbs and/or BCAA’s between meals seems like the most optimal plan if muscle-building is your current priority.