The Basic Concepts of Sport Nutrition

 Food and fluids can have a great effect on the way we feel and on the ability of the human body to perform repeated bouts of intense physical exercise. It is only when coupled with the correct form of training that diet can help improve and maintain optimum performance. Our choice of foods or ‘diet’ is one of the many important choices we all have to make.

Food choices are unique to each individual and depend on many factors such as availability, time, personal likes, along with mood and other psychological factors.

We believe the main dietary considerations are related to the following:

  1. Provision of carbohydrates to provide energy.
  2. Maintenance of fluid balance.
  3. Control of body fat.

An understanding of the body’s individual requirements and some nutritional knowledge enables athletes to select their own individual diet from the wide variety of foods available to us today. One way of assessing both individual foods and diets, is to compare the amount of energy (kcal) provided by carbohydrate, protein and fat. These figures can be expressed in terms of a percentage of the total energy in the food or diet.

Recommended percentage energy breakdown are as follows:

——-
Normal
Athlete
Carbohydrate
50%
50-60%
Fat
<35%
25-35%
Protein
10 to 15%
10 to 15%

These figures are guide-lines only. There is no single correct diet.

Some athlete chose to eat foods which have too much of their energy from fat and not enough from carbohydrates. Many individuals however, seem to have the balance about right.

Percentage Energy Calculations

For an individual food the calculation is very easy to do since the information needed can usually be obtained from the nutrition label on a food. You first need to know the amount of energy in a gram of each of the nutrients. This is expressed as either kilocalories (kcal) or kiloJoules (kJ). Strictly speaking, we should use the System International (SI) units of kiloJoules, but in some countries we tend to use kilocalories. (carbohydrate=4kcal/g, protein=4kcal/g, fat=9kcal/g).

To calculate the figures for one day’s food you need to keep a food diary, recording the weight/portion size of each food eaten. Using food tables or a suitable computer program and the label information, you then add up the total weight of each nutrient (carbohydrate, fat and protein) eaten during the day. You also calculate the total kilocalories in the day’s food.

  1. Multiply the nutrient weight in grams by the correct factor to give the amount of energy from the particular nutrient you are dealing with.
  2. Divide the answer by the total energy in the food (or day’s diet) and multiply the result by 100 to give a percentage.

General advice is that the diet should be primarily based on foods that contain vitamins, minerals and starchy (complex) carbohydrates. These include bread, rice, potato, pasta, cereals, fruit, dried fruit, fruit juice and vegetables.
A typical pre-match meal would have most of the energy from carbohydrate and little from fat. Choices could include soup, bread, potatoes, low fat pasta meals (not cheesy), baked beans, vegetables, salad, lean meat, skinless chicken, grilled fish, fruit and yoghurt.
For athletes doing large amounts of exercise it is sometimes necessary to eat sugary (simple) carbohydrates such as jam, syrup, honey, some biscuits, some cakes, sugary fizzy drinks and cordial drinks are included. These foods in general contain lower levels of vitamins and minerals and therefore should not be the main foods in anybody’s diet.
Fluid intake should be high. This is because water is the main transport medium within the body and is vital for temperature regulation. In addition, athletes often have high fluid losses due to sweating.
If an athlete wishes to lose bodyfat then they have to be more selective with their foods. They must still eat a high carbohydrate diet to provide the energy for exercise but try to reduce their intake of foods which contain fat and oil. These include cheese, pastry, sausage, burgers, peanuts, crisps, butter, margarine, some chocolate and some biscuits.

I hope that this brief summary will be of use to you and that you enjoy learning about nutrition as much as I do.