Diet © 2006 Pearson Publishing Tel 01223 350555

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

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

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

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

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

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

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

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

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

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

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

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