High-intensity trainings (e.g. running) are characterized by a considerable reduction of carbohydrate stores in our bodies. Carbohydrate is the main source of energy for the human body which is the reason why our bodies use this organic compound to refuel themselves during and after the training.

After depletion of carbohydrate stores during exercises the body still requires a lot of energy to refuel itself and the so-called "carbohydrate window" opens to convert available carbohydrate into energy for muscles. If you do not consume any carbohydrate-rich food or beverages within first 15-30 minutes following the workout, the body will use other energy sources which are protein and fat. Oxidation of fat for energy is much slower than oxidation of protein, thus protein becomes our body’s first choice in the absence of carbohydrates. However using protein for energy is very much undesirable as protein is a building material for our muscles.

The conclusion is clear: it is important to quickly compensate for the lack of carbohydrate while the carbohydrate window is open in order to convert carbohydrate into glycogen which is necessary not only for muscles but also for the normal work of the liver. Recommended carbohydrate intake after completing an intense workout is 0.7-1.5 g per 1 kg of body weight. The best option would be food with high glycemic index. Glycemic Index (GI) is the rate of conversion of carbohydrate contained in food into blood glucose (blood sugar) to refuel body energy and replenish glycogen stores. High GI foods include honey, jam, bread, potatoes, pasta etc.

When taking care of the post-workout "carbohydrate window", you should not forget about extra protein for the quick recovery of damaged muscle fibers. Thus eating food rich with both protein and carbohydrates would be the best decision. However consuming more protein and carbohydrates than it is required for the body to restore after the training may result in transformation of all superfluous nutrients into fat accumulating in the body.

In the process of intensive training such as running or racing, the digestive system slows down. This state persists for 30-40 minutes after the workout. Consuming solid foods is not recommended at this time. During this time period the most appropriate nourishment would be carbohydrate and carbohydrate-protein drinks – juices, green tea with honey, berry juice or special sports beverages. But in 30-60 minutes after the training you can start eating high GI or average GI foods.

Below is the real life runner’s post-training diet:

• immediately after the training: a glass of juice (300 g.) or a sports drink containing protein and carbohydrates;

• 30-40 minutes after the training: oatmeal with milk, raisins and honey. Honey can be substituted with a toast and jam.