The nutritional diet of runners is very important in ensuring maximum benefits to the sport. There is no magic food that will make an athlete a better runner overnight. However, the omission of certain foods and indulgence in others can and does affect athletic performance, sometimes very considerable. The basic requirement of a runner is an extra 1000 calories a day for every hour of running that is done. Therefore, an athlete running one hour a day requires 3000 calories a day - 2000 calories for a normal diet and an additional 1000 calories for the hour of running. Food that is high in calories includes meat, cheese, biscuits and anything that is fried when cooked. As much as possible, all athletes should try to stay away from such foods. Food that is low in calories and better for any athlete to consume is fresh fruit, vegetables and salads. When possible, it is always better to grill or poach your favourite foods instead of frying them.

It is a well-known fact that the staple diet for a runner is carbohydrates. This is because starch is preferentially oxidised for muscular work i.e. carbohydrates yields more calories per litre of oxygen than does the burning of fat. Hence, these are the reasons marathon runner's stay away from high carbohydrate foods the week before the race, and then stock-up a few days before the marathon. By staying away from carbohydrates the week before the race, the runner depletes the glycogen storage in his muscles. An excess consumption of carbohydrates few days before the race leads to an above average deposit of glycogen in the muscles, therefore, producing an above average storage of energy for the latter part of the marathon.

Body building foods, such as protein, minerals and some vitamins, allow growth, maintenance and repair of the body. Examples of such food are meat, poultry, fish, cheese, milk and milk products. Protein is an important part of an athlete's diet - it helps heal injuries to muscles and bones. The richest forms of protein foods are corned beef, cheese, dried peas and peanuts. Athletes who suffer a shortage of protein in their diet usually suffer fluid formation around the knee and other joints, in addition to muscular weakness and fatigue.

Another proven fact about the runner's diet is that more meals are better than fewer meals in a day. The result is improved performances in the runner. Studies have shown that five meals a day lead to a total work output of an athlete that is greater than that achieved from three meals a day. Also, smaller meals spread over short intervals in a day helps withstand intense cold weather, hot environments and higher altitudes.