Basic Guide to Nutrition
Before we get onto specific foodstuff, recipes etc., it is important to have an understanding of basic physiology. This understanding will enable you to make better and more informed decisions when constructing your own dietary requirements.
The Energy System
ATP(adenosine triphosphate) is the immediately usable form of chemical energy for muscular activity (by immediate we mean that when energy is released from ATP a portion of that energy goes directly to facilitate muscular contraction). The chemical energy stored in ATP comes, originally, from the foods we ingest. The process of intermediary metabolism “transfers” the chemical energy found in foods into the chemical energy stored in ATP. So you can see from this that without the correct fuel supply you will have a depleted energy system. What is generally meant by fuel supply is the type of foodstuff used for ATP production during exercise. There are three foodstuffs: Protein, Carbohydrate and Fat.
Protein can be used as an energy fuel but it is not normally a significant fuel during most forms of exercise. However, under conditions of very long endurance activity, protein will contribute anywhere from 5% to 10% of the total energy need. The main contribution of protein is to cellular and tissue growth and repair in thebody. Proteins are complex molecules containing Amino Acids.
Carbohydrate and Fat
There are two major factors that significantly affect the preference for and interaction of carbohydrate and fat fuels during exercise: the intensity and duration of exercise and diet – as exercise intensity decreases and duration increases, fat becomes the major source of fuel.
The importance of the relationship between nutrition and exercise performance is obvious: Good nutrition is essential to proper growth and development.
When studying nutrition it is important to take into account the following:
- Basic nutrients.
- Food requirements.
- Eating habits.
A Basic Guide to Nutrition
Our first interest is in basic nutrients, of which there are three classes:
- Energy nutrients (discussed above)
- Vitamins and minerals.
1. Vitamins and Minerals
Most vitamins are vital to the metabolism of fats and carbohydrates and are classified as water soluble or fat soluble.
Water soluble vitamins
These are vitamin C and the B complex. These are not stored in the body and must be constantly supplied in the diet. Since they are not stored, when they are taken in excess they will be passed in the urine.
Fat Soluble vitamins
The fat soluble vitamins – A, D, E, and K are stored in the body, mainly in the liver but also in fatty tissue. Whilst this means that these vitamins need not be supplied every day, it also means that excessive accumulation can cause toxic effects.
These are inorganic compounds found in trace amounts in the body and are also important to proper bodily function. Calcium, phosphorus, potassium, sodium, iron and iodine are a few of the more important required minerals.
Of all the nutrients water is probably the most essential for human life. Water makes up about 50% to 55% of our total body weight, 72% of our muscle weight and 80% of our blood is water. Water is important in the regulation of body temperature, and it is the medium in which all the body processes occur.
2. Food Requirements
Food requirements are dependant upon two major factors: nutritional needs and caloric needs.
Nutritional need: no one nutrient should supply 100%of the caloric intake. Of the total calories taken in, a certain proportion should be derived from each of the three food nutrients:
Protein 10% – 15% Fat 25% – 30% Carbohydrates 55% – 60% Caloric Needs: The calories taken in as food should be approximately equal to the caloric expenditure resulting from body maintenance and physical activities.
3. Eating Habits
It is essential to have good eating habits and this entails how to select foods and how many meals to eat per day (this can be dependant on your caloric needs). It is most common to select foods from the following four food groups:
- Milk and cheese.
- Fruits and vegetables.
- Meat and high protein foods.
- Bread and cereals.