Building Muscle with a Positive Protein Balance
Protein balance is nothing more than the difference between protein build-up and breakdown.
All the tissues in our body consist largely of protein. This (and therefore also our tissues, such as muscle, skin, hair, connective tissue, etc.) is constantly undergoing build-up and breakdown processes, so our body needs a continuous supply of fresh building blocks. The building blocks needed for tissue growth are called amino acids, which our body obtains from dietary protein during digestion. So, by eating dietary protein, we essentially supply our body with the building blocks it needs for tissue growth.
The ratio between the build-up and breakdown of body protein is called protein balance. Changes in protein build-up and breakdown are triggered by both training and nutrition. As a result, depending on your training and/or nutritional measures, your protein balance can rise or fall within a very short time, so that you ultimately build up (positive protein balance) or break down (negative protein balance) net protein mass. For example, strength training without any food intake does increase protein synthesis (protein build-up), but because protein breakdown also rises at the same time, it results in a negative protein balance (in other words, a net breakdown of body protein).
How does dietary protein affect protein balance?
The example above shows that even when a specific training stimulus increases protein synthesis, this does not result in an acutely positive protein balance without dietary protein, and therefore does not lead to an increase in muscle mass.
If, however, you combine strength training with the necessary amount of high-quality dietary protein, this quickly leads to a positive protein balance. The reason is that the additional dietary protein further boosts protein synthesis, which eventually outweighs protein breakdown. As a result, the body builds up tiny amounts of protein over time. The sum of these extremely small "protein build-up surpluses" leads to measurably more muscle mass in the long run.
Certain (essential) amino acids are responsible for the increase in protein synthesis caused by dietary protein. Because different protein sources contain these amino acids in different amounts and in different combinations, they affect muscle protein synthesis to varying degrees. More on that in a future article.
Alongside the protein source, the amount of dietary protein consumed is also key to increasing protein balance. Because muscle protein synthesis cannot be boosted indefinitely, and because excessively high total protein amounts drive up protein breakdown at the same time, there are biological upper limits to effective protein intake. It therefore makes no sense to consume protein amounts that are too small or excessively high in order to increase muscle protein synthesis.
Protein intake throughout the day
Additional protein intake throughout the day (for example, when protein needs are higher due to physical activity, or with "unbalanced" diets) aims to maintain muscle mass by having increased protein synthesis offset "natural" protein breakdown. The key point here is that as little as around 10 g of essential amino acids is enough to maximise the increase in muscle protein synthesis, whereas protein breakdown rises with protein portions > 20-25 g/portion. You should therefore aim to consume protein sources that are as "high-dose" as possible, with the highest possible proportion of essential amino acids. It therefore makes little sense to consume protein supplements that maximise protein synthesis per portion but, because of their high total protein content (for example, 40 g per portion), also unnecessarily drive up protein breakdown.
In future articles, we'll show you what "high-quality" protein actually means and how different proteins affect protein synthesis rates in different ways.
