science is still not able to explain exactly how a cell transforms food into energy. We just know it happens. And we also cant explain why the cell in the body needs certain foods, and not others, in order to function properly.
We do know that food is broken down in the body by combining with oxygen. We might say it is "burned" up like fuel. Now, the way we measure the work a fuel does is by means of calories.
A gram calorie" is the amount of heat required to raise the temperature of one gram of water one degree centigrade. The" large calorie" is 1,000 times as great. In measuring the energy value of food, we usually use large calorie.
Each type of food, as it "burns up", furnishes a certain number of calories. For instance, one gram of protein furnishes four calories, but one gram of fat furnishes nine calories. The body doesnt care which fuel is used for energy, as long as it gets enough of that energy from food to maintain life.
The amount of calories the body needs depends on the work the body is doing. For example, a man who weighs 150 pounds needs only 1,680 calories per day if he is in a state of absolute rest. If he does moderate work such as desk work, he needs 3,360 calories per day. And if he does a heavy work, he may need as much as 6,720 calories a day to keep the body functioning properly.
Children need more calories than adults, since older people cant burn the fuel as quickly. Interestingly enough, we use up more calories in winter than in summer. Suppose, however, we take in more fuel than we need? The body uses up what it needs and store some of it away for future use. The body can store away about one-third of the amount it needs each day. The rest becomes fat! And thats why we "wat
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