The primary consideration in achieving a balanced diet is not how much or how little we eat, but what we eat. The body is a high

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问题 The primary consideration in achieving a balanced diet is not how much or how little we eat, but what we eat. The body is a highly complex self-generator, that is to say, provided it is given the right fuel, it is capable of both curing and warding off disease. Like any other machine, however, if it is inexpertly cared for, over-taxed or insufficiently used, it will become rusty, sluggish or clogged and parts of its mechanism may even grind to a halt. The proper care of the body requires an understanding of its needs, allowing for variations resulting from climate, age or occupation. To keep in good running order, the body requires the raw materials for growth and the replacement of tissues when necessary. Our bodies burn food like fuel to produce the energy we need.Basically we need carbohydrates, protein, fat, vitamins and minerals, together with regular but not excessive exercise.
Carbohydrates are found in foods such as bread, potatoes and sugar. They are excel- lent energy producers, but if eaten too excess may be largely converted to fat and a reduction in the amount of carbohydrates or "starchy’ foods is one of the obvious ways to reduce weight, since most of us eat too much of them anyway. Protein, found in meat and cheese, is used for tissue building and in the developed countries most people eat about ll0g daily, which is a good deal more than the recommended minimum of 70g a day. In underdeveloped countries where food is scarce and periodical famine may occur, children in particular suffer from protein deficiency, since this is the material most need- ed for growth. Animal fats, e. g. butter, are also good sources of energy, but are some- times held to cause increased cholesterol levels in the blood (which may lead to fatty de- posits in the arteries) and are therefore best avoided by people suffering from certain forms of heart disease, vegetable fats being recommended as a substitute.
Vitamins are another essential requirement for health. There are about forty known vitamins, but the most generally referred to are A, B, C, D and E. Deficiency of Vita- min A, found in carrots, liver, etc., is alleged to affect the vision and the skin and re- duce resistance to infection. Vitamin C, present in nearly all fruit, particularly oranges and other citrus fruit, has come to be regarded as particularly effective in the prevention of colds and low energy states and claims have recently been put forward regarding the efficacy of large doses of Vitamin C in the treatment of certain mental illnesses.
Among the minerals we need, the most important are calcium, iron and iodine. Milk is one of the richest sources of calcium, which helps to build our bones and our teeth. Lack of iron in the blood produces anaemia and children and others suffering from anaemic conditions are generally advised to increase their intake of iron, which may be found in liver, molasses and dates among other foods.
In any diet, natural foods are best. In the Western world, at least, we have become increasingly dependent on "convenience foods": frozen peas, tinned meat and fish, ready-to-eat meals from the supermarket, anything which is quick to prepare, looks more or less appetising and satisfies our immediate hunger. We have ceased to care that most of what we eat has had the goodness processed out of it. We rely on pills to supply what our food lacks. We ignore the preservatives, artificial coloring and additives in the packaged foods we buy. In the kind of world we live in, however, there is, of course, no quick, easy answer.
Climate and work play an important part in diet. People in hot climates require fewer carbohydrates than those in colder regions, and those engaged in heavy manual labor or physical exertion, such as dockers or athletes, require more protein to keep them fit for their work. We are all individuals and a balanced diet must take into account genetics, environment, employment and, last but not least, emotional stress. Tension and anxiety are often the underlying causes of over-and underweight and even dietary deficiency since our nervous system needs to be fed as much as any other part of our body.

选项 A、a generator
B、regular replacement of its mechanisms
C、a balanced diet and excessive exercise
D、a balanced diet and regular exercise

答案D

解析 第—段中“The keep in good running order,the body requires the raw materials for growth and the replacement of tissues when necessary(这意味着“a balanced diet”)…together with regular but not excessive exercise"说明 D项符合题意。
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