3．
Increasingly, over the past ten years ,people—especially young people—have become aware of the need to change their eating habits, because much of the food they eat, especially processed food (加工过的食品)，is not good for health. As a result, there has been a growing interest in natural foods: foods which do not contain additives (添加剂) and which have not been affected by chemical fertilizers (化肥) widely used in farming today.
Natural foods, for example, are vegetables, fruit and grain which have been grown in soil that is rich in organic matter. In simple words, this means that soil has been nourished (给﹍营养) by unused vegetable matter, which provides it with vitamins and minerals. This in itself is a natural process compared with the use of chemicals and fertilizers, the main purpose of which is to increase the amount—but not the quality—of foods grown in commercial farming area.
Natural foods also include animals which have been allowed to feed more freely in healthy pastures(牧场). Compare this with what happens in the mass production of poultry(家禽)：there are battery farms, for example, where thousands of chickens live crowded together in one building and are fed on food which is little better than rubbish. Chickens kept in this way are not only tasteless as food; they also produce eggs which lack important vitamins.
There are other sides of healthy eating which are now receiving increasing attention from experts on diet. Take, for example, the question of sugar. This is actually unnecessary food. It is not that sugar is harmful in itself. But it dose seem to be addictive: the quantity we use has grown steadily over the last two centuries and in Britain today each person consumes an average of 200 pounds a year﹗Yet all it does is provide us with energy, in the form of calories. There are no vitamins in it, no minerals, and no fibre.