综合类考试AB级：阅读理解Pennsylvania
You hear this：“No Wonder you are fat.An you ever do is eat.”You feel sad：“I skip my breakfast and supper.I run every morning and evening.What else can I do？”Basically you can do nothing.Your genes，not your life habits，determine your weight and your body constantly tries to maintain it.
Albert Stunkard of the University of Pennsylvania found from experiments that，“80 percent of the Children of two obese parents become obese，as compared with no more than 14 percent of the offspring of two parents of normal weight.”
How can obese people become normal or even thin through dieting？ Well，dieting can be effective.but the health costs are tremendous.Jules Hirsch，a research physician at Rockefeller University， did a study of eight fat people.They were given a liquid formula providing 600 calories a day1.After more than 10 weeks，the subjects lost 45kg on average.But after leaving the hospital，they all regained.The results were surprising：by metabolic measurement，fat people who lost large amounts of weight seemed like they were starving.They had psychiatric problems. They dreamed of food or breaking their diet2.They were anxious and depressed;some were suicidal.They hid food in their rooms.Researchers warn that it is possible that weight reduction doesnt result in normal weight，but in an abnormal state resembling that of starved non-obese people.
Thin people，however， suffer from the opposite：They have to make a great effort to gain weight.Ethan Sims，of the University of Vermont，got prisoners to volunteer to gain weight.In four to six months，they ate as much as they could.They succeeded in increasing their weight by 20 to 25 percent. But months after the study ended，they were back to normal weight and stayed there.
This did not mean that people are completely without hope in controlling their weight.It means that those who tend to be fat will have to constantly battle their genetic inheritance if they want to significantly lower their weight.
The findings also provide evidence for something scientists thought was true-each person has a comfortable weight range3.The range might be as much as 9kg.Someone might weigh 60-69 kg without too much effort But going above of below the natural weight range is difficult. The body resists by feeling hungry or full and changing the metabolism to push the weight back to the range it seeks.
词汇：
obese adj.肥胖的
metabolic adj.新陈代谢的
psychiatric adj.精神病的
注释：
1. They were given a liquid formula providing 600 calories a day.他们被给予一种流食配方，每天提供600热卡。
2. They dreamed of food or breaking their diet.他们梦中吃食品，或是不是只吃规定的食品。
3. The findings also provide evidence for something scientists thought was true-each person has a comfortable weight range.结论还证实了科学家认为是正确的一点，即每个人的体重有一个适当的幅度。
练习：
1. What determines your weight？
A)Your working manner.
B)Your eating habit.
C)Your life style.
D)Your genes.
2.What did Jules Hirsch do in his study？
A)He let the eight fat people skip supper.
B)He let the eight fat people skip breakfast.
C)He let the eight fat people run every mornin8 and evening.
D)He gave the eight fat people a liquid formula providing 600 calories a day.
3.What happened to the eight fat people after they left the hospital？
A)They went mad.
B)They killed themselves.
C)They were back to normal weight.
D)They attempted suicide
4.What did Ethan Sims make his subjects do？
A)Battle their genetic inheritance.
B)Increase their weight.
C)Stay at home.
D)Lower their weight.
5. What did scientists think was true？
A)Each person has a fixed weight range.
B)Each person has a weight range of 9 kg.
C)Each person wants to control his weight.
D)Each person wants to eat to his hearts content.