Nutrition guide for cyclists: Lexicon - For road cyclists: The lexicon of sports nutrition

Anyone who trains intensively burns a lot of energy and needs regular refuelling. In our ABC, we explain what is behind the most important technical terms in nutritional science.

The glycaemic index (GI) indicates how quickly the carbohydrates in a food enter the blood and how much they increase the blood sugar level over a defined period of two hours. With a high GI, the blood sugar level usually rises quickly and remains at a high level for longer, which is particularly useful in the final phase of a competition.

Isotony In isotonic drinks (electrolyte drinks, juice spritzers in a juice/water ratio of 1:1 to 1:3 with a relevant sodium content), the concentration of dissolved particles is about the same as in human blood. They can quickly compensate for training-related fluid loss and, depending on their composition, provide energy from carbohydrates. Sodium compensates for sweat-related losses.

Hypotonic drinks such as mineral-rich mineral water or thin juice mixtures in a ratio of 1:3 to 1:5 have a lower particle density than the blood. This allows the water to be absorbed by the body very quickly and the minerals more slowly. They are suitable for drinking when energy requirements are low, e.g. during basic training.

Hypertonic drinks (undiluted juices, soft drinks or energy drinks) have to be diluted in the body and therefore remove some water from the gastrointestinal tract. They are therefore only suitable during exercise when a lot of energy is needed quickly but there is no risk of dehydration, for example on long climbs in low temperatures.

Macronutrients Proteins, fats and carbohydrates. The latter two are the basic substances for human energy production. During energy metabolism, carbohydrates and fats are converted into energy, while proteins promote cell formation during regeneration or muscle building.

Micronutrients Vitamins, minerals, trace elements and secondary plant substances are vital for the body as it cannot produce them itself. Minerals, especially sodium, help racing cyclists to compensate for large sweat losses on hot days. Potassium replenishes glycogen stores during the regeneration phase. Calcium and magnesium losses can be compensated for with mineral-rich water.