Озаглавьте последний абзац. 3. Найдите в тексте ответ на вопрос, содержащийся в заглавии.

No record exists to tell us who first began to think about why we eat or about various effects of foods, but the ancient Greek philosophers and doctors commented along these lines. Socrates said, the purpose of food is to replace the water lost through the skin and the loss of heat from the body. Hipocrates, the “father of medicine”, thought that growing bodies should have more heat than those of older people and so require more food, that neither overeating nor fasting is a good idea.

Lavoisier thought that the combustion¹ that produces body heat should occur in the lungs, but later several chemists could show that the oxygen combines with the red corpuscles of the blood and is carried to the tissues in all parts of the body to supply energy where it is needed.

Understanding of the composition of foods and what happens to them after they are eaten had to wait for several discoveries in chemistry. What happens to food from the time it is eaten until it is oxidized to produce heat and mechanical energy, could not be learned until the chemical nature of foods was discovered. And the foods appear to be very complex organic substances.

Foods are composed of organic substances far too complex to be understood with the state of chemistry as it was in the first half of the nineteenth century. Modern work on digestion and nutrition began about a century ago.

Although scientists had attempted to learn why we eat, they could learn very little. We might sum up their accomplishments by saying they learned that all animals inhale oxygen, combine it with the food to produce carbon dioxide, heat, and the energy with which they could move about. The chemistry of that time could not tell more.

Now we know that we should eat to have energy. When the nutritionist uses the word “energy” he means the capacity to do work. To him “work” is movement. All work requires energy and work involves motion; therefore, the more a person moves about, the more energy he requires. Even when a man is asleep he is still partly in motion because his heart, lungs and most of the other organs are working.

Письменно переведите текст на русский язык.

Very little natural food can serve as nourishment just as it is, glucose is about the only natural substance that can. While chemists were trying to find what foods are made of, physiologists were trying to learn just what food must be used as nourishment.

It soon became evident to the physiologists that foodstuffs must undergo enormous changes in the human body, because the body tissues are profoundly different from the foodstuffs that nourish them. There is very little carbohydrate in the animal body and human fat is not much like either the vegetable fats or milk fat. Certainly the hair, skin and muscles bear little resemblance to the proteins of eggs, milk or wheat.

The word “food” is used loosely to designate anything edible whether it is a natural product such as wheat, fish, or potatoes, a partially processed product such as flour; or cooked foods such as an apple-pie. If it is edible it is food regardless of what must be done to it before it is eaten. Because of this uncertainty of meaning, the nutritionists use the word “food-stuffs” for those portions of the foods the body can use, mainly the carbohydrates, fats and proteins.

All digestion is a reaction of the foodstuffs with water or what the chemist calls a hydrolysis. As the digested food passes along the intestines¹ it consists of 3 sugars, mostly glucose, about 20 amino acids, glycerol and several fatty acids. There are also salts and some other substances that were in the food, such as acids, chlorophyll, cholesterol and vitamins. Such is the food as it passes through the intenstinal wall into the blood stream to be distributed to the various tissues for growth, repair, or the production of energy.

а) как определяется пища с научной точки зрения;

to utilize, utilization – использовать, применять, использование, применение;

to be high in/to be rich in – быть богатым, иметь высокое содержание,

to be low in/to be deficient in – быть бедным, иметь низкое содержание;

involved in (Part. II в функции определения) – связанный с

1. Переведите на русский язык данные словосочетания.

several sugars responsible for a sweet taste of certain foods, differ from each other, give sweet taste, more complex in nature, an intermediate step, vegetable origin, blood stream, plant body, as needed, to give bulk and provide material, regulatory processes, coarse fibered vegetables, considered together with carbohydrates, total solids.

The sugars, starches and cellulose are known as carbohydrates. These are composed of the chemical elements: carbon, hydrogen, and oxygen.

The term “sugar” to most people means cane or beet sugar, which is sucrose. However this is only the most common of the several sugars responsible for a sweet taste of certain foods. Milk, fruit, vegetables contain sugars other than sucrose. The different sugars in foods differ from each other, but all give the foods in which they are present a characteristic sweet taste.

Starch is a carbohydrate more complex in nature than any of the sugars. Like sugar, it is built by the combination of carbon, hydrogen and oxygen. The production of sugar by the plant is an intermediate step in the manufacture of starch.

Although carbohydrates are mostly of vegetable origin, sugar is found in the blood streams of animals and of man. Provision is made in the cells of the liver for storage of animal starch (glycogen) sufficient to meet requirements of the human body for carbohydrates for a comparatively short time. The animal body, like the plant body, synthesizes this more complex substance from sugar and later hydrolyses it to sugar as needed.

Cellulose is also a carbohydrate, containing the elements present in starch in the same proportion. Cellulose used in the diet is to give bulk and provide material for certain regulatory processes. Foods high in cellulose are bran, dried fruits and legumes, fruits with skins, seedy fruits, and leafy and coarse fibered vegetables.

The organic acids, found in a large number of foods are frequently considered together with carbohydrates. The utilization of organic acids in the body for energy is similar to that of starches and sugars.

Organic acids also have a part in stimulating and regulating body processes. Fruits and vegetables are the best sources of organic acids. Citric and malic acids are examples of those commonly found in these foods.

Only a few foods consist of pure carbohydrate. A well-known example of these is sugar. A food is considered high or low in carbohydrates according to the amount it contains in proportion to its total solids. Foods high in carbohydrates are: cakes, candy, cereals and cereal products, dried fruits, honey, potatoes, sugar.

1. What substances are known as carbohydrates? 2. What is sugar responsible for? 3. How is starch built? 4. What is the role of cellulose? 5. What do you know about organic acids? 6. What foods are high in carbohydrates?

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