Basics of sports nutrition
Carbohydrates, in the form of glucose, is the main fuel that is used during physical activity and is stored in the muscle and liver in the form of glycogen. When doing sports, the stored glycogen is consumed. The muscle and the liver can usually store enough glycogen for 60 to 90min (up to max 120min) of intense physical activity. If you have ever run into the “wall” while doing sports, you know how it feels to have completely emptied the glycogen stores. Since the carbohydrates help the fat metabolism with the energy readiness and you have just consumed all the carbohydrates, nothing works anymore. The fat metabolism cannot take over until some carbohydrates are digested and ready to start both metabolism again in the form of glucose. The glycogen stores must therefore be replenished continuously during a competition by carbohydrate-rich drinks and foods. This supply of carbohydrates can impressively delay muscle and general fatigue and enable a continuous high level of performance. Since the body requires less oxygen to burn carbohydrates (compared to fats and protein), carbohydrates are considered the most important fuel for athletic performance.
How is energy measured and measured?
Energy is officially measured in joules. However, since calories have been used as a unit of measurement for many, many years, calories are still somewhat more common and the switch to joules is progressing slowly.
1 Calorie = 4,184 Joules
Proteins are the nutrients that are mainly responsible for the construction and repair of muscle and other body tissues as well as for the production of important enzymes and hormones. Under normal circumstances, proteins hardly contribute to the provision of energy. In certain situations, however, especially if too little is eaten (hypocaloric nutrition) or in later competition phases of long competitions, when the glycogen stores are completely emptied, then unfortunately skeletal muscle can be decomposed and used as fuel. The latter example can be a necessary sacrifice in a competition, depending on the situation, the former, on the other hand, is completely undesirable in daily training (training does not start, the metabolism decreases, it should build up).
A balanced diet covers the protein needs of most athletes: poultry, beef, lamb, pork, fish, eggs, dairy products and vegetable protein sources such as tofu, nuts, seeds and kernels. Protein is formed from variable combinations of small building blocks called amino acids. Some amino acids are produced in our body itself by arranging various small components, while other amino acids (the so-called essential amino acids) can only be supplied from the outside with the diet. Protein from animal sources has a good selection of amino acids including the essential ones, while proteins of plant origin show a different pattern: they typically contain an excess of one (or more) essential amino acids, but they lack the variety for this. If vegetables and fruits make up the main part of the diet, this can become a problem, for example, for vegetarians. If the selection of these plant sources is done consciously and in a variety of ways, the need for proteins can still be met, including the essential amino acids, since different plants contain different proteins and many of the plants then complement each other. The usual daily recommended amount of protein in the diet for a recreational athlete is 1g/kg of body weight. For game athletes, strength athletes in a maintenance phase and endurance athletes, the daily protein requirement is slightly higher (1.2–1.4g) and can usually still be covered by the basic diet. During growth and puberty (2g), but also during intensive training phases for endurance athletes, the protein requirement is increased (1.7g).
This requires careful planning in order to cover the recommended amount and to distribute the four servings of protein (e.g. meat, fish, eggs, cheese or protein of vegetable origin alternately) sensibly. In the latter situations, targeted, additional protein supplementation to achieve the recommended daily dose seems useful.
Fats are the main fuel for long loads and are crucial for the transport and absorption of fat-soluble vitamins. Fats have more than twice as much potential energy as protein or carbohydrates (9 calories per gram of fat versus 4 calories per gram of carbohydrate or protein) and they form a virtually unlimited source of energy, since it has enough of them stored in muscle fibers and in fat cells to make more than 100h of exercise possible. However, in order to be available as fuel, fats need enough oxygen, which must be metabolized at the same time. So fat is the fuel for low and moderately intense loads and it helps to save glycogen, even in high-intensity loads. Most of us have sufficient fat reserves. It is also important to know that the body often immediately converts any kind of excessive energy intake, regardless of its origin and source (fats, carbohydrates, proteins), into fat and stores it as body fat.
Every athlete should include certain amounts of healthy fats in the daily diet, such as nuts, vegetable oils (e.g. olive or rapeseed oil), a portion of butter or another spread (10g). For each additional hour of training, half a portion should be additionally incorporated. This clearly shows that fats also have their place and importance and contradicts the myth that fats are simply bad. What still applies, on the other hand, is that fats in biscuits, chips or fries, fried food or even fats of animal origin, e.g. in sausages really should only be enjoyed with mass.
Frequently asked questions – Myths and facts
One of the most common questions during the consultation is: why did I run out of juice? Why did I just run out of strength there? Just nothing came anymore? Am I not deficient and should I take supplements?
A frequent observation, which sports nutrition experts and sports doctors make again and again, is that athletes quite often have a gap in their energy supply. At the same time, most often they believe that this could almost certainly have to do with a specific shortage situation. A situation that could then be remedied with supplementation. Even with extensive blood sampling and further laboratory tests, such a deficiency situation is found only very rarely. Very often, on the other hand, when we take a close look at the food and drink of these athletes at the competition and immediately before, there are clear errors in the provision of energy.
- Insufficient energy supply for the whole day, especially during long-lasting competitions
- Missed meals are not sufficiently replaced
- Poor planning (‘We only ate something small when we just had time’ or ’There was unfortunately nothing but fries and hot dog')
- Irregular drinking and irregular eating in the days before the competition, due to the arrival and stress in the preparation
Eliminating all fat in the diet: Athletes who intend to reduce body weight, in particular the body fat percentage, ask: "What should I do? Now I have not eaten fat for a long time and still nothing happens to my weight?” In this situation, the first thing to do is to clarify exactly what the athlete has for goals. Of course, this includes checking whether a weight reduction is necessary at all or not. Secondly, it is about clarifying that it is not the fat, but all three fuels: carbohydrates, fats and proteins, which contribute to energy intake. And if the energy intake is higher than the energy consumption, the excess calories are stored as body fat, regardless of their origin. At the same time, the recommendation is to slightly limit the energy intake and slightly increase the energy consumption (e.g. with repeated, low to moderately intense endurance units, possibly even a sober training).
Sports nutrition = carbohydrates. It is a strong opinion, athletes only need to eat carbohydrates. About two years ago, a group of scientists claimed the opposite: ‘No, you have to do exactly something else, namely focus on fats.' As if in the first case carbohydrates or in the second case fats were the only sensible source of energy for athletes.
It is correct that carbohydrates play the main role in providing energy for physical activity and regeneration, and at the quantitative level, carbohydrates are the most important nutrient. But as stated above, it would be negligent and would not do justice to the importance of fats and proteins in the diet of performance-oriented athletes if the latter were missing. After all, even if they play a minor role quantitatively, they cannot be replaced by anything. This means that sports nutrition is a ”both- and" function: the main fuels in sports are: = carbohydrates + fats + proteins.