大学英语自学教程(中)

大学英语自学教程(中)

16-A. Heart Disease: Treat or Prevent?

One of the greatest killers in the Western world is heart disease. The death rate from the disease has been increasing at an alarming speed for the past thirty years. Today in Britain, for example, about four hundred people a day die of heart disease. Western healthcare systems are spending huge sums of money on the surgical treatment of the disease.

This emphasis on treatment is clearly associated with the technological advances that have taken place in the past ten to fifteen years. In this time, modern technology has enabled doctors to develop new surgical techniques and procedures. Many opeations that were considered impossible a few years ago are now performed every day in

U.S. hospitals. The result has been a rapid increase in heart surgery.

Although there is no doubt that a large number of people benefit from heart surgery, critics of our health-care systems point out that the emphasis on the surgical treatment of the disease has three clear disadvantages. First, it attracts interest and financial resources away from the question of prevention. Second, it causes the costs of general hospital care to rise. After hospitals buy the expensive equipment that is necessary for modern heart surgery, they must try to recover the money they have spent. To do this, they raise costs for all their patients, not just those patients whose treatment requires the equipment. The third disadvantage is that doctors are encouraged to perform surgery -- even on patients for whom an operation is not at all necessary

-- because the equipment and surgical expertise is available. A federal government office recently said that major heart surgery was often per-formed even though its chances of success were low. In one type of heart surgery, for example, only 15 percent of patients benefited from the surgery.

In the recent past, medical researchers have begun to emphasize the fact that heart disease is associated with stress, smoking and a lack of exercise, and we can often reduce the risk of heart disease by paying more attention to these factors.

More and more people are realizing that there is a connection between heart disease and the way they live. As a result of this new awareness, attitudes toward health are changing. In the past, people tended to think that it was sufficient for good health to have a good doctor who

could be relied on to know exactly what to do when they became ill. Now they are realizing that merely receiving the best treatment for illness or injury is not enough. They are learning that they must take more responsibility for their own health. Today many people are changing their dietary habits and eating food with less fat and cholesterol. Many are paying more attention to reducing stress in their lives. The number of smokers in the United States is now far below the level of twenty years ago as many people succeed in breaking the habit and as fewer people take it up. More and more people are aware of the benefits of regular exercise like walking, running, or swimming; some have begun to walk or ride bicycles to work instead of driving. Millions have become members of health clubs and have made health clubs one of the fastest growing businesses in the United States today. And now the

beneficial effects of these changing attitudes and behaviors are beginning to appear: an encouraging decrease in deaths from heart disease.

16-B. Dieting Four Way to Health

Almost everyone considers going on a diet sometime in his or her life. All, regardless of sex and age, have something in common -- losing weight and losing it fast.

Though their common aim may seem basically good, they probably do not realize that misguided dieting can do more harm than good to their health. Going on too strict a diet can destroy the balance of chemicals in the human body. This happens because when the body is suddenly given much less food than usual, it feels as though it is being attacked and tries hard to protect itself by saving energy. It does this by slowing down metabolism, the process by which the food we eat is converted into energy. As energy

is supplied to the body at a slower and slower rate, dieters gradually become so weak that they can do nothing. They soon lose interest in everything going on about them, and their resistance to illness becomes so low that they are easily attacked by one illness after another.

Most of those who diet know that foods like rice, bread, potatoes, cakes, sweets, fruits and some vegetables contain carbohydrates, and so can make one fat. What they do not realize, however, is that carbohydrates are our bodies’ main source of energy, and that these foods also contain components essential for the composition of substances that are needed to keep the body healthy. As a result, they try to avoid eating these foods, and consequently, they become weaker and less healthy. They begin to have difficulty sleeping properly and start to suffer from radical mood changes. In more serious cases,

they even begin to show signs of mental illness.

1t is strange enough that most strict diets recommend artificial sweeteners to take the place of sugar and other natural sweeteners. In fact, such artificial sweeteners actually increase one’s appetite and lead to one’s eating even more than usual.

Of course, the fact that misguided forms of dieting result in so many problems does not mean that no dieting is safe or all dieting is harmful to the health. Proper dieting can not only help a person lose ugly excess fat, but can also help him or her to keep it off and to lead a more active, happier and healthier life.

You might ask just what a proper diet is. Well, simply expressed, a proper healthy diet is one that is well-balanced, or, in other words, one that includes enough but not too many of the kinds of foods that provide

the body with the nutrients that it needs to function properly. The most important of these nutrients are the macronutrients: proteins, carbohydrates and fats. The body needs fairly large amounts of proteins and carbohydrates for building material and energy. Meat, fish, eggs, milk, cream, and nuts all contain proteins and foods like rice, bread, potatoes, etc. contain carbohydrates. The body needs fat to keep it from the cold and to provide a protective layer for the organs, but only in small quantities.

Vitamins and minerals such as iron, calcium, are another group of essential nutrients, though the body does not need as great a quantity of these as it does the macronutrients - proteins, carbohydrates and fats.

There are two types of vitamins, water-soluble vitamins and fat-soluble vitamins. Water-soluble