There are new findings that not enough sleep may cause people to gain weight.Researchers s

There are new findings that not enough sleep may cause people to gain weight.Researchers say a lack of sleep can produce hormonal changes that increase feelings of hunger.
In one study,researchers in the United States examined information on more than 1000 people.The people had taken part in a long-term study of sleep disorders.
Some people slept less than five hours a night.They had 15 percent higher blood levels of a hormone called ghrelin than people who slept eight hours.And they had 15 percent less of the hormone leptin.Experts say ghrelin helps make people feel hungry;leptin makes you feel full.
The scientists say these hormonal changes may be a cause of obesity in Western societies.They note the bination that limitation is mon and is widely available.
The results were not affected by how much people exercised.People who are awake longer have more time to burn energy.But the researchers say loss of sleep may increase hunger especially  for high-calorie foods,so people gain weight.It seems that,for survival,the body may be designed to store more fat during times with less sleep.
Researchers from Stanford University in California and the University of Wisconsin did the study.They found that the best amount of sleep for weight control is 7.7 hours a night.
The Public Library of Science published the findings in its journal Medicine.Internet users can read the full study,free of charge,at plos.org.
【小题1】Which of the following shows the right way in which lack of sleep causes weight gain?A．more ghrelin and less leptin→feeling hungry→eating moreB．feeling hungry→eating more→more ghrelin and less leptinC．burning more energy→feeling hungry→eating moreD．more leptin and less ghrelin→feeling full→less exercise【小题2】The two words missing in the 4th paragraph should be “    ”and “    ”.A．weight;sleepB．sleep;foodC．hunger;foodD．weight;work【小题3】When you sleep 7.7 hours a night,you will    .A．have your ghrelin level rise and leptin level dropB．have your leptin level rise and ghrelin level dropC．have your ghrelin and leptin levels properly balancedD．feel neither hungry nor full【小题4】The writer wrote this passage to    .A．make a news reportB．offer a piece of medical adviceC．make an advertisementD．keep a record of the research findingsA