Fast food and too much TV time shouldn’t take all the blame for（对…承担责任） the weight problems. A group of researchers say that a number of aspects（方面） of modern living---- from lack of sleep to environmental chemicals and to living with air conditioning(空调) ----may be closely related to the weight problems of many people.
Lack of sleep is one factor（因素）. Research in animals and humans suggests that a lack of sleep over a long period of time can increase appetite（食欲）. Studies also show that many adults and children are sleeping less than they used to. In recent decades（十年间）, adults have gone from sleeping for all average of nine hours to about seven hours.
There is also evidence that industrial chemicals may increase body fat. These chemicals, which are used in products, change hormonal（荷尔蒙） activity when they get into the body. Studies suggest that people have been getting more and more of these chemicals through the food chain in recent decades.
Another factor that may be making people overweight is air conditioning. The body burns calories when forced to control its own temperature, and people tend to eat less in hot and wet weather, but air conditioning makes it unnecessary for the body to make any adjustment（调整）.
Researchers also list other possible risk factors for overweight, including more older mothers, whose children may become overweight more easily; a number of medicines which can lead to weight gain; and fewer people who smoke, since people often gain weight when they stop smoking because nicotine can make people eat less.
No one is suggesting that people should stop working and sleep more, or keep smoking. When it comes to any person’s weight, what really matters is how much they eat and how much of the food they use every day. That means diet and exercise are still the key.
Title： 71 related to（与…..有关的） the weight problems
| Situation | Researchers say that not only fast food and too much TV time but also many aspects of modern living should take the blame for 72 . | |
| Three main factors | 73 | l increase appetite. l reduce average sleeping hours from 74 to about seven hours. |
| Industrial chemicals | l increase 75 . l change hormonal activity. l be got through the food chain. | |
| 76 | l people tend to eat less in hot and wet weather, l air conditioning makes it 77 for the body to make any adjustment. | |
| Other possible factors | l more older mothers. l a number of medicines. l more people who 78 | |
| 79 | what really matters is how much they eat and how much of the food they use every day. The key to person’s weight problem is 80 . | |
