The Link between Protein and Sports

In the category of macronutrients, proteins remain a key nutrient for athletes as they are directly linked to the structure of muscle cells. Muscle mass gain is often closely associated with protein intake, especially among bodybuilders. For endurance enthusiasts (trail running, ultra marathons, long-distance triathlons, 100k races, etc.), the focus is more on seeking nutritional support during races through complementary carbohydrate intake, as well as improving and optimizing recovery and tissue repair after physical exertion (which aligns with bodybuilding in this aspect). It’s worth noting that proteins are one of the macronutrients, along with carbohydrates and fats. I will address proteins as a whole, discussing which ones to consume, the recommended quantity, and where to find them.

What roles do proteins play during and after exercise?

Amino acids are the main component of proteins and muscular proteins (first and structural role of the amino acids). While performing a long and/or intense exercise, those amino acids are used to provide energy to realise the physical effort. Even if the use of those amino acids is relatively done in small quantities, it has important consequences on how muscles work. Right after the physical effort, the body automatically enters a phase of muscular proteins reconstruction (called anabolism). This body activity strongly depends on the availability of amino acids, as much as on several hormonal signals including insulin. Thus, proteins and amino acids supply after the effort will help the muscular reconstruction. For better efficiency, a simultaneous intake of certain carbohydrates like glucose is recommended as it enhances the production of insulin.

How many proteins do you need ?

The average recommendation is a supply from 1,2 to 1,5g per kg of corporal weight and per day for the endurance athletes (e.g. between 84g and 105g per day for a 70kg athlete). It can reach 2g per Kg per day for strength athletes whose aim is to improve muscular mass. For this intake to be qualitative, the athlete has to provide at least 2/3rd of proteins through natural food and the rest under the form of high biological value proteins (meaning easily assimilable by the body). The downfall is that some athletes, thinking they’re doing right, inverse this ratio, resulting in an imbalance of the protein/lipid/carbohydrate ratio and of the daily ration micro nutritional density.

When eat proteins ?

The best moment to take proteins is the early recovery phase (meaning right after the effort), during which the muscular anabolism is very high, and requires a lot of amino acids (the muscular bricks). I usually recommend a 10 to 20g intake 15 to maximum 30 minutes after the exercise (especially if this is a long or intense one, body weight considered). I advise to eat the proteins during the stretching moves that happen usually during the 10 minutes after the effort. This one time supply must be integrated to the general daily supply (meals +/- snacks + post exercise food intake including recovery drinks. Remember that it’s admitted to have an equivalent supply of carbohydrates (simple and complex) to potentiate the muscular recovery. This action synergy is global when a lipid supply is associated. It’s a complex intake (regarding its composition) that has to be brought to the body. In association, it’s important to balance the supply of potassium, magnesium, vitamin B … which also have a physical importance.

On another hand, during the effort, especially during the endurance and the ultra endurance (100km, ultratrail, Ironman…) and as explained before, the proteins’ structure is affected. We therefore find an increase of the consumption of amino acids, used for the production of energy. However, this rise is limited which leads to a deterioration of muscular proteins, and eventually an amplified central nervous fatigue, especially during the long lasting and intense efforts (UTMB Mont Blanc Ultra Trail, …). Thus, the protein supply during an Ultra is highly recommended (all proteins and especially the Branch Chain Amino Acids BCAA).

How much quantity ingest during those long lasting and/or intense trials :
– Proteins: minimum 5g per effort hour
– BCAA: between 1 and 2g per effort hour to have an efficient result

Informations about the branch chain amino acids (BCAA), especially for the stamina sports

We frequently read that the nutrients needed for the physical efforts are essentially carbohydrates (glucose, fructose, maltodextrin…), sodium and some others minerals and vitamins. However they’re not the only necessary ones and we can add to them the branch chain amino acids (BCAA), which are part of the protein category. A lot of searching teams from the Sport Sciences are going through the consumption of BCAA during a long lasting effort as they help diminishing the deterioration of muscular proteins, delaying the reducing of muscular glycogen stocks and could reduce the central nervous fatigue.

Information: We call BCAA 3 essential amino acids : leucine, isoleucine and valine.

Quality of the protein intake : animal ou organic ?

How to bring proteins inside the sport related nutrition: drinks, protein based energy bars, every day food (see below).

A protein balanced alimentation has to provide every necessary amino acids (or essentials because they’re not synthesised by the organism): tryptophan, lysine, methionine, phénylalanine, isoleucine, leucine, valine that is to say 8 essential amino acids (EAA). High biological value proteins own a strong percentage of those EAA among all amino acids : generally 40% minimum. Usually, animal proteins (milk, dairies, eggs, meat, fish…) are very digestible and offer a wide variety of EAA. They are complete proteins, opposed to organic proteins (leguminous plants, fruits, protein seeds, seaweeds, cereals) which are rather deficient in sulfured amino acids and lysine. Pea proteins, soy or even seaweed like spirulina are exceptions as they present a complete profile interesting for the athlete. Thus, it’s important to wisely associate different sources of organic proteins in order to cover the entire need of EAA throughout the day.

To optimise your supplies, it is common to complement 2 protein aliments that have different limiting EAA. Here are below some types of associations allowing to get a good protein balance :

•  Cereals (limiting EAA: lysine) + leguminous plants (limiting EAA: sulfured AA but rich in lysine)
• Cereals + oilseed (2 sulfured EAA missing)
• Cereals and/or leguminous plants + seaweeds (8 EAA)
• Cereals + vegetables rich in lysine like green peas, cabbages, mushrooms, green beans…
• Cereals and/or oilseed + soy (8 EAA)

Conclusion on proteins

The protein question has to be treated in a global vision, interacting with other nutrients (carbohydrates, lipids, vitamins, minerals, trace elements…), and not in an isolated way among the schemes of nutritional care of the athletes. The protein interest is real and accurate as the idea of recovery is a key of the performance realisation. It’s therefore strategic to potentiate day after day the protein intake, in a balanced quantity and qualitative manner. Then, and this information is crucial, it is well known that in our current society, most of the nutritious supplies are coming from animals… but for how long? Indeed, we witness the emergence of more and more organic protein sources like peas proteins, micro-algal …On the animal side, insects are in the first plan… Everything is possible provided that it never harms the sustainability of mankind through time. One thing is certain, the modern consumer is willing to eat natural, which he admits is what does him bests.

Nicolas AUBINEAU
Dietitian Sports Nutritionist