单选题
If you have been on a diet and reached your goal,
chances are good that when you stop dieting you will regain all the weight you
lost. After several weeks on a low-calorie diet——900 calories or fewer——the body
conserves energy by slowing the speed at which it bums calories. This slow-down
explains in part why your weight loss may cease after a few weeks.
When you eventually return to eating a normal amount of food, your body
may continue to burn calories at the slower rate, storing the remaining calories
as fat. So if you are on a strict diet, your body may need fewer calories to
maintain the same weight; losing weight becomes more difficult.
Doctors know that as you gian weight the fat cells in your body (most of us
average 30 billion of them) become enlarged. But there is a limit to how big a
fat cell can get, and very fat people develop additional fat cells——sometimes
more than 100 billion. It now appears that you can add fat cells at any point
during your life, although the number you have is influenced by a combination of
your history of dieting and your genetic makeup. Fat cells are
different from other cells. They are made mostly of fat instead of protein, and
apparently they never go away, even after dieting. Instead, they merely shrink.
Dr. Jules Hirsch of Rockefeller University has examined the body tissue of very
fat people who have lost weight, and found that it resembles that of starvation
victims. Perhaps, he supposes, it is the billions of undersize, "hungry" cells
that drive many formerly fat people off their diets. New
research suggests that your hungry cells aren't the only signal senders that
tempt you toward the refrigerator. Another criminal may be the hormone insulin.
Insulin turns sugar and fat into fuel for the body. In addition, some
re-searchers believe that high levels of insulin are a factor in hunger and
appetite-and may drive you to overeat. Exercise helps maintain
your weight and seems to bring insulin levels down, says Dr. Donald S.
Robertson, a medical director. "Any weight-loss program must fail", he says,
"unless it incorporates a certain amount of exercise."
单选题
When you stop dieting, you will regain the weight you lost because
______ .
A. your appetite has become greater than before
B. the fat cells you have are influenced by gene from your parents
C. your body can now consume only part of the calories you get from
food
D. the fat cells in your body have become larger and larger
【正确答案】
C
【答案解析】
单选题
What tempts you toward the food is ______ .
A. fat cells
B. hungry cells
C. hunger and appetite
D. both hungry cells and hormone insulin
【正确答案】
D
【答案解析】
单选题
The passage implies that ______ .
A. overweight results from fat cells
B. keeping a diet is not the best method of losing weight
C. it is hungry cells that prevent you from dieting
D. if you want to lose your weight, you should go on a strict diet
【正确答案】
B
【答案解析】
单选题
According to the text, it can be concluded that ______ .
A. you become fat again because you stop dieting
B. there are many factors that lead to overweight
C. it is the hormone insulin that makes you fat
D. it is difficult for the fat people to lose weight
【正确答案】
B
【答案解析】
单选题
Which of the following would be the best title for the text?