Nutritional Effects on Performance

Balanced Diet Whatever the sport or activity, it has now become widely recognised that nutrition is of great importance. A well balanced diet is essential for optimum performance in both training and during competition.

Balanced Diet Athletes place enormous demands on their bodies when competing at the highest level, and to enable the body to function at its peak during the daily regimes, an adequate diet is needed. Not only should the athlete’s diet be designed to provide the energy required during exercise, but it should also provide the necessary nutrients for tissue growth and repair and those needed to keep the human machine functioning at its optimal level.

The Six Essential Groups of Nutrients Carbohydrate Fat Protein Vitamins Minerals Water

Balanced Diet

Balanced Diet You also need to make sure that you have enough vitamins and minerals, fibre and water in your diet. If you do a lot of endurance work you might need to increase your carbohydrate intake to 60-65%. Remember – after a heavy training session it can take up to 24 hours to fully replenish the glycogen stores, so the following days training needs to be relatively light.

Some Food Facts Endurance training helps the body to use more fats during sub maximal exercise. Protein supplements are not needed for body-building, providing a balanced diet is eaten. Caffeine helps to mobilise fatty acids in the blood.

Some Food Facts Carbohydrates drinks are not much use for activities that last for less than 40 minutes. Any meal before an activity should be eaten at least two hours before the start time and should be high in carbohydrate and low in fat. Regularly drink small amounts of water or glucose drinks during long endurance events and intermittent exercise to avoid dehydration and hypoglycaemia. Don’t wait until you feel thirsty.

Diet and Exercise We need to eat to obtain enough energy to complete our daily tasks; We have to keep pace with our body’s metabolism (the sum of all the chemical reactions that take place within the body).

Diet and Exercise Basal metabolic rate (BMR) is a measure of the amount of energy we would use if we remained at rest. Our daily intake of food has to cover the BMR plus any additional energy for other activities such as exercise.

Diet and Exercise Men can usually consume 2800-3000kcal a day and women 2000-2200kcal a day without putting on weight. If you are particularly active or train regularly you will probably need to eat 5000-6000 kcal a day.

Diet and Exercise By eating the same amount of energy as you use you will maintain a constant body weight. BMR varies from person to person. Also age varies you BMR. Your BMR will slow down as you get older, so don’t expect to be able to eat as much as you do now without putting any weight on.

The Athletes Diet What you eat before, during and after exercise will have a direct effect on how you perform, either in training or in competition. Athletes undertaking daily training sessions need a high energy intake through eating carbohydrates, which should form up to 60% of total energy intake.

The Athletes Diet Research points to athletes having 4-6 small meals a day rather than 2-3 larger ones. This ensures that muscle and liver glycogen stores are kept topped up throughout the day.

The Athletes Diet One big misconception by novice athletes is to consume sugary foods prior to training or competition in order to boost glucose and therefore energy levels. Glucose levels are increased through consumption of sugary foods, but high levels of blood glucose cause an increased release of insulin which eats away at the body’s energy stores depleting them more rapidly than if the sugary food or drink had not been consumed.

The Athletes Diet (Day of Competition) On the day of competition or if there is going to be a particularly hard training session, the athlete should eat a meal high in carbohydrates 3-4 hours before commencing to keep blood glucose levels high throughout the duration of the competition. If you are involved in heats or bouts of work over the day, it will be necessary to top up glycogen stores by consuming small amounts of carbohydrates. Fluids also must be replaced.

After the Event Following the competition or training, it is necessary to refuel the body as soon as possible in order to resynthesise muscle and liver glycogen stores. A high carbohydrate meal should be eaten within two hours of the cessation of the exercise to start this refuelling process. Water and isotonic supplements should also be taken to replenish those lost through sweating and aid re-hydration.

Glycogen Loading (Carbohydrate Loading) Diet Glycogen Loading (Carbohydrate Loading)

Glycogen Loading Some athletes seek to manipulate dietary intake before competitions in order to optimise performance. One method of doing this is by glycogen loading or super compensation.

Glycogen Loading This process involves depleting the glycogen levels seven days prior to the event by doing endurance-based training, and then starving the body of carbohydrate over the following three days by omitting such foods from the diet. For the remaining days leading up to competition the athlete will consume high carbohydrate meals to boost muscle glycogen stores up to twice that normally stored.

Glycogen Loading This method of manipulation is widely practised in endurance events and maximises energy production via the aerobic pathway. Recent research has shown however that total depletion of glycogen may not be necessary for trained athletes.

Glycogen Loading The three days of carbohydrate starvation will causes great fatigue, and lead to an increased risk of injury and possibly kidney problems.

Glycogen Loading Simply resting for three days prior to competition and eating high carbohydrate meals may maximise glycogen stores. It is important to point out however that storage of glycogen requires a great ingestion of water and water intake must increase accordingly. This will obviously be of use anyhow to the athlete, since it will help prevent dehydration during the endurance race.

Summary (To Be Used After Completing the Diet Presentation)

Summary A well balanced diets is essential for successful performance in sport both whilst and in preparation for competition. Six groups of nutrients should be included in an athlete’s diet. These are carbohydrates, fat, proteins, vitamins, minerals and water. Carbohydrates in the form of sugars and starches is the main energy provider for the high intensity athlete – is stored in the muscle and muscles and the liver.

Summary Fat is the major source of energy in the body and is mainly used during low intensity endurance based activities. Stored fat is broken down into free fatty acids – its usable form. The body cannot use fat alone but uses a combination of fat and glycogen.

Summary Proteins are composed of amino acids, the body’s building blocks. They are also an energy provider, but are only used when glycogen stores are very low. Vitamins can aid energy production. Given a well balanced diet there should be no need for supplementation.

Summary Minerals are vital for tissue functioning, transmission of nerve impulses and enable effective muscle contraction.

Summary Water is an essential nutrient. Water loss during exercise can impair performance in a number of ways. It certainly contributes to heat stroke and can induce muscle cramps.

Summary Athletes should ensure they receive adequate energy supplies. A high carbohydrate diet of up to 60% of total energy intake is essential. Many small meals are better than 2 or 3 larger ones. Glycogen loading or super compensation is a form of diet manipulation to ensure the energy stores of the body are at their greatest prior to a competition.

Your Next Task Read pages 140 –143 in your text book (new book) or the relevant pages in the old book