The energy value (0) of food is measured in calories. A man, lying in bed all day would need about 1 700 calories (1) day to prevent him from losing weight. If he got up and did an hour of light work, like typing, he (2) need about another 75 calories. Needs vary with the weight of the body, but on the whole the amount of food needed depends (3) the work done.
     Modern nutritional science (4) made it clear that the quality of food we eat is no less important (5) its quantity. Everyone needs an adequate and balanced diet (6) help them keep warm and fight off disease, and children, in particular, need good food to grow (7) strong and healthy. There are three good categories of foodstuffs and a good diet comprises balanced amounts of all three. One of the most basic types of food is carbohydrates, like sugar. (8) second main type is protein, like meat, fish, cheese, eggs and milk. These are less important (9) a source of energy and heat but vital for building up the body. The third type is fats, (10) provide concentrated energy. In Britain the most popular source of fats is butter.