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

• 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

There are two main categories of amino acids:

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