From the ancient Olympic Games to the present day, the control of per diem expenses has been used as an attempt to improve physical performance in sports. The writings of ancient Greek philosophers and physicians report different strategies that athletes developed in the realm of the human and the divine, combining food and magic, to prepare for their competitions. Athletes consumed animal meat -beef, goat, bull or deer-, fresh cheese, wheat, dried figs, wine and some special 'concoctions'.

Today, athletes are still looking for in food, and in the 'magic' of different nutritional supplements -such as vitamins-, that small advantage to improve a tenth of a second or two centimeters in the sporting performance. A tiny difference that means going from oblivion to glory. But can nutrition help you succeed in sport? Undoubtedly, yes.

A clear case in point is soccer. It is an accepted fact that muscle glycogen - i.e. the glucose stored in the muscle - is crucial to a player's performance. Thus, to achieve adequate muscle reserves, an adult soccer player's diet should contain about 500 grams of carbohydrates per day. This translates into a varied and balanced per diem expenses where potatoes, bread, rice, fruit, legumes, cereals and pasta are the main ingredients. The player who accumulates less glycogen before the start of the match runs less meters and runs more slowly.

Paula Radcliffe is another example of the close relationship between per diem expenses and sport. This British marathon runner arrived at the 2004 Olympic Games in Athens with the world record under her arm and became the undisputed Gold medal contender. However, she was not able to finish her agonizing participation. She ran out of strength a few kilometers before the goal. Fans remember how she always stayed in the lead of degree program, without eating or drinking, until she suffered the "pájara": a condition associated with insufficient levels of glucose in the body that forced her to abandon the race.