You can only exert physical effort when your body/muscles are getting enough fuel. This is logical, since physical effort requires muscular work, which is only possible when there is sufficient energy for our muscles to function. You could compare this to a car with an empty petrol tank. The car won’t get very far, and neither will an athlete if he or she has not filled up with enough fuel before or during activity. Carbohydrates (sugars) are the best source for delivering fuel and generating muscular work. Fats are also capable of supplying energy, and have the advantage of being able to supply more energy than carbohydrates. 1 gram of fat contains 9 kcal, while 1 gram of carbohydrate only contains 4 kcal. But fats suffer the disadvantage of not being viable as a fuel in every sporting scenario. An athlete can only use fat as an energy source if several requirements are met:
- Firstly, there must be sufficient oxygen supply to burn fat. Research has shown that the effective burning of fat requires that the heart rate does not exceed 60-70 per cent of the maximum heart rate.
- Carnitine is an important compound that is required for burning fat. Without carnitine, an athlete will burn fat less effectively. This is important information for vegetarians, since animal products are rich in carnitine.
- An athlete who is less well trained in the use of fat as an energy source will have trouble using fat when exerting effort. Training after fasting is the best way to train your body to use fat for energy. During training after fasting, our bodies are forced to use fats instead of carbohydrates. In doing so, the body produces fat burning enzymes that we need to convert fat into glucose. During a competition, an athlete who does not have these enzymes will have more trouble burning fat and will only be able to use carbohydrates.
It is important that athletes consume sufficient building materials to help build up cells. A muscle consists of thousands of cells, which can be damaged by exercise. This damage must be repaired in order to prevent muscle degradation and facilitate muscle growth. Fat and protein are important sources of building materials, and are therefore essential for athletes.
In general, athletes require more protective nutrients in the form of vitamins and minerals. Due to overworking and excess fertilisation, our agricultural land has been degraded, so that fruit and vegetables now contain less vitamins and minerals than roughly 50 years ago. This lower level of vitamins and minerals, combined with lower consumption of fruit and vegetables in general, means that athletes have to pay extra attention to consuming sufficient fruit and vegetables in their diets. Variety is also very important here.
Our level of performance is directly proportional to our loss of moisture. With this in mind, it is important that we pay enough attention to hydration. Drinking enough before, during and after exercise is of crucial importance to preventing dehydration and loss of performance.