1. Diet
© 2006 Pearson Publishing Tel

2. Food
Food is the body’s source of energy and basic building blocks, enabling muscle movement, growth and repair
The food we eat should come from seven groups:
Carbohydrates
Fats
Proteins
Vitamins
Minerals
Fibre
Water
Each of these has a distinct job in fulfilling the body’s dietary needs

3. Carbohydrates
When broken down, carbohydrates provide the body with glucose, the main source of energy
Although energy can be gained from other sources, carbohydrates can supply energy quickly and efficiently
Excess carbohydrate in the body is directed to the liver and converted to glycogen, which is stored in the liver or muscles
Other excess carbohydrate may be stored as fat

4. Carbohydrates There are two types of carbohydrates:
Simple carbohydrates — sugars found in jams, cakes, chocolate, milk and sugar itself
Complex carbohydrates — starches found in vegetables, cereals, rice, pasta and bread
Simple carbohydrates are absorbed directly into the bloodstream, providing a rapid source of energy for a short period of time
Complex carbohydrates are more important in supplying the body with a constant source of energy

5. Fats
Fats can release high levels of energy but require a large amount of oxygen to do so
They provide an energy source when resting and sleeping
Fat is stored in a layer beneath the skin
It keeps the body warm and protects vital organs

6. Fats There are two types of fats:
Saturated fats — found in animal products such as meat, cheese, milk and cream
Unsaturated fats — found in fish oils and products made from vegetable seeds such as sunflower and corn
Saturated fats contain cholesterol, which can clog arteries and lead to high blood pressure and heart disease
Fats are broken down into fatty acids and glycerol during digestion

7. Proteins Proteins are the building blocks of the body
They repair and replace damaged tissue and build new tissue for growth
During digestion, they are broken down into their constituent parts, amino acids
21 types of amino acids are needed for our bodies to work properly

8. Amino acids There are two main categories of amino acids:
Essential amino acids (8 types) — these cannot be produced by the body and therefore have to be provided by the food eaten, eg by meat, fish, beans, nuts, eggs and poultry
Non-essential amino acids (13 types) — these can be produced by the body

9. Vitamins Vitamins have four main functions:
They regulate chemical reactions in the body
They help release energy from food
They maintain resistance against disease
They help with growth and the repair of tissues
For example, vitamin C is needed to form collagen, a key component of all connective tissues
Vitamins are found as traces in food substances, including fresh fruit and vegetables

10. Minerals Minerals are inorganic chemicals found in most fresh food
The more a person exercises, the greater the mineral intake needed
Excessive mineral salt can contribute to high blood pressure

11. Minerals Minerals include:
Iron — helps produce red blood cells which carry more oxygen around the body preventing fatigue — found in red meat and green vegetables
Calcium — helps blood to clot, aiding recovery from injury, and strengthens bones and muscles — found in milk, cheese and cereals
Iodine — aids normal growth, essential for athletes as it helps energy production — found in milk and saltwater fish

12. Fibre
Fibre plays an important part in the process of digestion and is the non-digestible part of fruit, vegetables and cereals
The main functions of fibre are to provide the bulk for food, encourage slow, even release of sugars and prevent constipation

13. Water Water makes up two-thirds of our body contents
There is a constant loss of water throughout the day — this must be replaced to prevent dehydration