Energy

Energy is needed to by the body to stay alive, to keep warm and to be active.  It is provided by the food and drink that we eat and is measured in either joules or calories.  A kilocalorie (or Calorie) is roughly equivalent to 4 joules.

• The amount of energy you need in a day will vary from person to person.  Your needs depend on your age, weight, sex and activity levels.  Broadly speaking, the average adult female requires 2000kcal a day whereas males require 2500kcal per day.
• All food and drink (except water) contains at least some calories, in the form of carbohydrate, fat, protein and/or alcohol.  Fat provides the most calories per gram but alcohol provides almost as much energy as fat.  Most foods consist of a mixture of carbohydrate, protein and fat, but the relative proportions will vary depending on the type of food.
• Energy is stored as fat in the body.  When the diet provides more energy than is needed, either because of overeating and/or lack of exercise, the excess is stored as fat and the person gains weight.