The role of nutrition in sports performance

Al Gondi

To maximise performance in sports, the athlete needs to consider nutrition an important component of good health and of sporting performance.

Optimum nutrition may help maximise athletic performance in five ways: By maximising energy stores, achieving ideal weight, ensuring sufficient minerals and vitamins, maintaining adequate hydration and optimising pre-competition and competition food intake.

Carbohydrates and fats are the two most important sources of energy required in sporting activities and they help in maximising energy stores. Protein makes a relatively minor contribution, but becomes more significant with the depletion of carbohydrate stores and inadequate energy intake.

Glucogen

Carbohydrate is stored in the liver and skeletal muscle as a form of glycogen (sugar). When required for energy, glycogen is released and broken down to provide the glucose necessary for energy. Glycogen stores are limited and need to be replenished daily.

The average amount of energy available from the stored carbohydrate would only provide fuel to run a distance of about 40km.

Endurance training increases the capacity of the muscles to store glycogen. Fat provides the body’s largest store of potential energy. The energy storage capacity of fat is twice more than the equivalent quantity of carbohydrate or protein.

Body fat content varies considerably from one athlete to the other. However, even the leanest of the athletes would have enough energy stored as fat to run a distance of 1,200km.

The fuel the body uses depends on the intensity and the duration of the exercises as well as the fitness and nutritional status of the individual.

Energy for short duration or high intensity exercise (usually lasting between one to two minutes) is almost entirely supplied by glycogen stored in the skeletal muscles.

Anaerobic exercise

Carbohydrate is the only nutrient that provides energy when the muscles have insufficient oxygen for their needs. This is anaerobic exercise and it produces lactic acid, which impedes the immobilisation of fat from adipose tissue.

This further increases the reliance of muscles on glycogen as their supply for fuel. Fat does not provide significant source of energy during periods of high intensity training. Its breakdown is too slow to meet the athlete’s demands. Fuel for long duration or moderate intensity exercise is supplied by fat in higher proportions.

During moderate exercise, certain hormones come into play and promote the release of free fatty acids from adipose tissue into the blood stream.

The longer the time spent exercising, the greater the contribution of fat as fuel. Endurance increases the capacity to break down fat for energy and preserve glycogen.

An important role of the athlete’s diet is to supply sufficient carbohydrate to fill the glycogen storage sites in muscle.