FIT for LIFE Knowledge Base Nutrition

Protein for Endurance Athletes

Proteins are necessary for very many tasks in the body and have a great importance for all athletes.

Protein is not a single substance. Protein is rather a class of substances in which an enormous number of different substances are combined. In our body, we even have blueprints for around 20,000-30,000 different proteins. Their functions are correspondingly diverse: as scaffolding in bones, muscles, skin and hair, as components of organs such as the liver, kidneys and heart, or as hormones and enzymes for controlling metabolism inside and outside the cells.

Each protein has a limited life span. For example, the protein that serves as the scaffolding of muscle is completely replaced every 120 days. Every day, part of it is broken down and must be built up again to the same extent. Otherwise, the muscles would shrink. Muscle work increases this degradation, and the rebuilding requires accordingly somewhat more protein.

Which proteins are broken down more depends on the type of physical work. As a result of strength training, for example, more scaffold protein is broken down in the muscle, while during endurance training it is other muscle proteins that are broken down. The reconstruction that follows the breakdown can be somewhat improved by a higher protein intake. However, it is not necessary to consume large amounts of protein for this, but rather to supply it at the right time – namely as close as possible to the activity. More protein is therefore also necessary in endurance sports. However, it does not lead to a (significant) increase in muscle mass as in weight training, but ultimately contributes to improving endurance performance.

The quality of protein comes into play when only a single protein source or purely vegetable proteins are used in the diet over a longer period of time (1). If our protein comes from different sources (e.g. milk, dairy products, meat, fish, eggs, cereals, etc.), the proteins complement each other and there is no need to worry about the overall quality of the mixtures.

More muscles with animal protein

If you want to target muscle building, you’ll do better with animal proteins than with vegetable proteins. Among animal proteins, whey protein is the favorite (2). However, the right training stimulus is much more important than the protein source. With moderate endurance training, one should not expect strong muscle growth, because the mechanical stimulus on the muscle cell is simply too low. Today, a generally accepted recommendation in sports is about 1.5 grams of protein per kilogram of body mass per day (3).

Ideally, the protein should be distributed over the main meals. An additional portion immediately after training and – if it is tolerated in terms of digestion – one before bedtime round off the ideal distribution. Even if it is surprising for many: The additional protein requirement is the same in endurance sports as in strength sports (or even team sports). Separate recommendations for endurance and strength are therefore more likely to originate from marketing strategies.

More than 2 grams per kilogram of body weight does not make sense for any athlete, since no additional benefit can be expected. Rather, at some point it can also be too much of a good thing. Some excess protein can indeed be broken down well via a healthy liver. However, at around 3 grams or more per kilogram of body weight, the breakdown stops halfway and the ammonium that accumulates in the blood leads to metabolic disorders, especially of the brain. Therefore, the daily amount that it is better not to exceed is 3 grams per kilogram of body mass (4). The recommendation of about 1.5 grams of protein per kilogram of body weight can be well covered by natural foods. Protein shakes are therefore not a must in sports. However, they can certainly make life a little easier in practice and make meal planning more convenient. The disadvantage: The higher comfort and the greater convenience must be bought over a higher price than with natural foods. Whether shakes or groceries, is thus to a good extent also a question of the wallet.

Nutrition expert Dr. Paolo Colombani is a scientific consultant with his independent practice.

(1) Sarwar Gilani G et al. Br. J. Nutr. 2012; 108 Suppl 2: S315–32
(2) Cermak NM et al. Am. J. Clin. Nutr. 2012; 96: 1454–64
(3) Phillips SM, van Loon LJC. J.Sports Sci. 2011; 29: S29–S38
(4) Rudman D et al. J.Clin.Invest. 1973; 52: 2241–9 

Text from FITforLIFE– This blog post was provided to us by the Swiss magazine FIT for LIFE. If you want to read regularly informative knowledge articles in the field of running and endurance sports, click here.