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Carbohydrates in sports - everything you need to know in general!


Carbohydrates are so important for you as an athlete

Carbohydrates in sports – a much-discussed topic

That carbohydrates are the most important source of energy for athletes is actually beyond question. Nevertheless, voices are raised again and again, which praise the so-called “low-carb”. There are many different names and types of low-carb, including some for athletes.

Basically, it is usually wrong to classify a thing as perfectly good or bad. Rather, one should always deal with it critically.

Some more myths around sports nutrition are revealed by Robert Gorgos in an article on our KNOWLEDGE CENTER site.

Thus, there are also situations for athletes in which low-carb training sessions are useful, for example. to train the fat metabolism. Nevertheless: According to current knowledge, the training and competition goals of athletes are generally not compatible with a low-carb orientation.

In order to withstand the training loads, to regenerate properly and to be able to call up performance, there is no way around an adequate supply of carbohydrates in sports.

Consequences of carbohydrate deficiency (during diets) 

An undersupply of energy can have serious consequences (not only) for athletes. If too few carbohydrates are consumed, this can lead, for example, to an increased risk of injury, weakened immune defenses, concentration problems, hormonal imbalances and developmental and growth disorders. A drop in performance is also to be expected – demonstrably.

You can read more about this topic HERE read.

In the course of a simulated eleven-day training camp, for example. investigated what effects the composition of a diet had on the athletic resilience of athletes. It became apparent that when a high-carbohydrate diet (8.5g per kg of body weight) was consumed, the athletes’ exercise capacity (measured in running units) deteriorated by around 3%. In contrast, a lower-carbohydrate diet (8.5g per kg body weight) reduced exercise capacity by about 7%. So the risk of exercise overload can increase if carbohydrate intake is too low.

In addition to a drop in performance, other signs of overexertion were evident, including mood swings. Again, differences were found between the two diets. A higher intake of carbohydrates appeared to reduce, but not prevent, the frequency of mood swings. [1]

This is how high the carbohydrate requirement is for athletes 

The need for carbohydrates generally increases in direct proportion to the duration and intensity of training. The longer and more strenuous the load, the more glycogen stores of muscle and liver are emptied. To fill these again, carbohydrates must be supplied.

For an occasionally active person, who does a casual workout now and then, it is sufficient to cover about 45-55% of the daily calories in the form of carbohydrates. For athletes, however, the intake should be significantly higher: Endurance athletes should cover 55-65% of the daily calories supplied by carbohydrates. This corresponds to an intake of 5-8g of carbohydrates per kg of body weight (CHO/kg bw).[2]

Athlete 75kg Athlete 55kg
5g per kg KG = 375g 5g per kg KG= 275g
8g per kg KG= 600g 8g per kg KG= 440g
Carbohydrate intake between 375g and 600g per day Carbohydrate intake between 275 and 440g per day

The intake recommendation increases when the athlete is in an intensive training or competition phase. Here the values increase to 8-10g CHO/kg bw.[2]

Athlete 75kg Athlete 55kg
8g per kg KG= 600g 8g per kg KG= 440g
10g per kg KG= 750g 10g/kg bw= 550g
Carbohydrate intake between 600 and 750g per day Carbohydrate intake between 440 and 550g per day

The right carbohydrates for energy

Not all carbohydrates are processed by the body in the same way. If you add carbohydrates during exercise, some are used more quickly than others.

Quickly used can be, for example: Glucose, sucrose, maltose, lactose, maltodextrin and amylopectin. Slower available are e.g.: Fructose, galactose, isomaltulose or amylose.

Why, for example, is fructose not as readily available to muscle as glucose?

These so-called “slow carbs” must first be converted in the liver before the muscle can use them. Fructose is processed in the liver to glucose, which is then available to the muscle. This process makes fructose a source of energy that is not immediately available to the body.

Carbohydrates supplied during exercise are oxidized at rates of 1g/min. This oxidation rate of 60g/h cannot usually be exceeded by any single carbohydrate source, slow or fast. This means that if you were to supply 100g of glucose per hour, only 60g would be used after all.[3]

However, for long, intense workouts, amounts of up to 120g carbohydrates/h are recommended. So is this recommendation wrong? How can this work if only 60g/h can be oxidized?

The solution is the following: The right carbohydrates must be combined.

Going into the exact physiological process to explain why this works is beyond the scope here. It is important to know that more than one carbohydrate source is needed for amounts above 60g/hr. There are several combinations which have proven to be successful. For example: Maltodextrin:Fructose, Glucose:Fructose, Glucose:Sucrose:Fructose [4].

On the other hand, it is much easier to use pre-prepared mixtures of special sports food, then intakes of 100g or more per hour are possible, provided that this is regularly “trained” (“train the well”).

Whether carbohydrates are available to the body quickly or slowly, by the way, has nothing to do with whether they are, good or bad carbohydrate sources.

The question of whether there are carbohydrates that are particularly suitable for athletes or those that are better left alone will be dealt with in another article.

Carbohydrate intake after training

Carbohydrates are at least as important in sports after training as before or during training. If you miss the chance to fill your glycogen stores after exercise, you miss a chance to recover faster and better.

You can learn more about the right timing of the KH supply HERE.

Especially for athletes who have little time for regeneration between two units, it is fundamental to use it in the best possible way. 

Through a combination of carbohydrates and proteins you achieve an optimal regeneration effect.  How this looks exactly, you will learn in detail in another article.

Carbo Loading before the competition – the right way!

I’m sure everyone has heard of Carbo Loading. This process,  which we describe in more detail in this article , is very popular and often used.

Again, start the race with full glycogen stores. For trained athletes it is sufficient to start Carbo Loading two days before. Glycogen stores are filled by reducing exercise and increasing carbohydrate intake. 

Approx. 8g carbohydrates/kg bw should be supplied per day. However, it is important to remember that increased carbohydrate intake does not equate to necessarily higher energy intake.

If the carbohydrate intake is increased, slightly less fat should be consumed in return. Whether the recommended amount is supplied via solid or liquid carbohydrates is irrelevant. Drinks containing carbohydrates, gels or bars are also suitable for this purpose. (Jeukendrup and Gleeson, 2010).

[1] M. Mountjoy et al., “IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update,” Br. J. Sports Med., vol. 52, no. 11, pp. 687-697, 2018, doi: 10.1136/bjsports-2018-099193.
[2] L. B. Baker, I. Rollo, K. W. Stein, and A. E. Jeukendrup, Acute effects of carbohydrate supplementation on intermittent sports performance., vol. 7, no. 7. 2015.
[3] A. Jeukendrup, “A step toward personalized sports nutrition: carbohydrate intake during exercise,” Sports. Med., vol. 44, no. SUPPL.1, 2014, doi: 10.1007/s40279-014-0148-z.
[4] R. L. P. G. Jentjens, C. Shaw, T. Birtles, R. H. Waring, L. K. Harding, and A. E. Jeukendrup, “Oxidation of combined ingestion of glucose and sucrose during exercise,” Metabolism., vol. 54, no. 5, pp. 610-618, 2005, doi: 10.1016/j.metabol.2004.12.004.

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Robert Gorgos

Robert Gorgos

Robert is a authority when it comes to sports nutrition science. As a nutritionist, he coaches many well-known top athletes, including the professional cyclists from BORA – hansgrohe. At the same time, he is a competitive athlete himself. And: Robert has developed the sports nutrition of MoN Sports.

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