There is (rightly!) a lot of focus on protein in an athlete’s diet. And there are also a lot of misconceptions out there. So in this short blog we go right back to basics on what protein is, why we care so much, and then the practical aspects of how much, what sort and when we eat it (aka total, type and timing!).
What is it, and why do we care?
Unlike carbohydrates and fats, protein is not a key fuel in the body. It is a key building block. A primary component of all the tissues in the body is protein. The dry weight of muscle is about 70% protein! So to repair, build, adapt and grow in response to training we need protein!
The recommendation for anyone who trains regularly is to consume 1.2-2.0g protein per kg bodyweight per day. This is quite a broad range, so how do we narrow it down to what might be most appropriate for any one individual. There are a few things to consider …
What is the nature of your sport? Typically, the more strength based your sport, the higher end of the range you will need.
How heavy is your training load? Typically, the heavier your training load and so the more stress and damage you exert on your body, the higher your protein need to support the repair of damaged tissue.
How high is your body fat? Typically, the higher your body fat the lower the protein required per kg of body weight, because a larger proportion of your body weight is tissue (fat) that is not heavily protein dependent.
Are you trying to lose weight? If you are losing weight, a high protein diet may help preserve muscle mass. Muscle may be preferentially lost in weight loss, particularly if you are already relatively lean. In fact, for individuals who resistance train a protein intake of as much as 2.3-3.1g/kg of fat free mass (not total bodyweight) may be optimal.
What are your fat and carbohydrate needs? We can think of our total calorie needs a bit like a bank balance. The more we spend on protein, the less we have to spend on fats and carbohydrates. So you will want to flex your protein intake based on your carbohydrate and fat needs too.
Protein is made up of amino acids. There are about 20 different amino acids, of which about 9 are essential. Essential amino acids are ones we cannot make in the body from other amino acids, and so must consume in the diet. Muscles are over 1/3 essential amino acids!! A complete protein is one that contains all the essential amino acids in sufficient quantities to optimise protein synthesis in the body.
Any one plant protein is typically not a ‘complete’ protein. This is not a problem, it simply means we want to combine complementary plant proteins (i.e. those low in different essential amino acids) in any one meal or snack to create a complete protein. The combinations to put together (and the amino acids that they are deficient in) are:
Something else to consider when we are deciding on what protein sources to include in our diet are protein powders. There is a common misconception that protein powders are somehow ‘better’ sources of protein than whole foods, because they are typically used in research. In fact, the reason we typically use protein powder in research studies is simply because they are simple, rather than superior. They contain (more or less) just protein. Which means we can conclude any effect we see is due to … protein. Whereas most whole foods have a whole combination of micronutrients and potentially other macronutrients too, so if we saw some sort of effect from eating that food we could not conclude exactly which element (or combination of elements) in that food was driving the effect. However, more recently studies have started to look at the effects of whole foods compared to protein powders and in many cases it is found that the whole food appears to have a superior effect on things like muscle protein synthesis! For example, whole milk was found to be superior to whey in one study, and whole eggs compared to egg whites in another. There appears to be something about the ‘food matrix’ that can push protein synthesis beyond that which can be achieved from protein alone. Something to consider!
Again, protein is unlike fats and carbs. Protein cannot be stored for later use in the body. So if we eat more than we can use in any one meal, it will simply be converted to other non-protein things, like fats and carbs. It will not be stored.
This means that to optimise protein synthesis in the body, we want to aim to consume protein regularly through the day, in sufficient doses. What do we mean by a ‘sufficient’ dose? One of the amino acids, leucine, is a key activator of the protein synthetic pathway in the body. So in every meal we want to have enough of this amino acid to activate the pathway and so help us use the protein we have eaten effectively. As we understand it about 1.8-3g of leucine per meal is sufficient, which typically equates to about 20g of high quality complete protein.
From a practical perspective, we would say take your total protein intake for the day and divide it into equal regular doses, at least every 4-5 hours through the day. And to provide protein to support overnight protein synthesis it may be advisable to have the final ‘dose’ of protein just before bed.
In summary, protein is pretty fundamental! We wouldn’t get far as a human without it. And as an athlete it is a fundamental component of the key tissues powering your performance …
Jager et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. JISSN, 14:20
Schoenfeld, B.J. and Aragon, A.A. (2018). How much protein can the body use in a single meal for muscle building? Implications for daily protein distribution. JISSN, 15:10.
Kerksick et al. (2018). ISSN exercise and sports nutrition review update: research and recommendations. JISSN, 15: 38