Energy from Food

From DT Online

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.