Energy from Food

Energy is required for all metabolic reactions which allow the body to carry out its functions: growth and maintenance of a healthy body is achieved by a regular intake of nutrients in food.

Foods which supply energy: Three main nutrients provide the body with energy.

• protein
• fat - provides the most concentrated source, weight for weight.
• carbohydrate - important source of energy. Carbohydrate acts as a 'protein sparer' so that the protein can be used for its primary functions.

The main energy supplying foods are:

• fats - ie. butter
• oils - ie. vegetable oil
• fatty foods (eg. egg yolk and cheese) sugar, cereals and starchy vegetables.

The amount of energy used by the body is the energy expenditure which differs from individual to individual:

• Young children require more energy for their size than adults due to rapid growth.

• Physical Activity v. sedentary workers - i.e. a clerical employee requires less energy than a very active worker - i.e. a coal miner.

• Basal Metabolism or resting metabolism - where the energy is released to keep the body alive - i.e. for warmth.

• Losing Weight - the energy intake from food must be less than the energy used for body activity, in this way the body is forced to use fat as its energy source.