a number of aspects of modern living -- from lack of sleep to exposure to living with air conditioning -- may be feeding Americans' weight woes. Fast food meals and TV time shouldn't take all the blame for the U.S. obesity problem, according to a research review published Tuesday. In fact, a group of researchers contend, a number of aspects of modern living -- from lack of sleep to exposure to living with air conditioning -- may be feeding Americans' weight woes. Writing in the International Journal of Obesity, they argue that obesity research and prevention efforts need to look beyond the "Big Two" -- food industry practices, like beefed-up portion sizes and added sugar; and reduced physical activity from factors such as cuts in school gym classes. That's not to say that diet and exercise aren't important. However, the evidence linking obesity to food industry marketing and lack of gym class is circumstantial. Lack of sleep is one, they say. Research in animals and humans suggests that chronic sleep deprivation boosts appetite and eating, and studies also show that U.S. adults and children are sleeping less than they used to. In recent decades, adults have gone from sleeping for an average of 9 hours to about 7 hours, the researchers point out. Another factor potentially weighing Americans down is air conditioning. The body burns calories when forced to regulate its own temperature, and people tend to eat less in hot, humid weather. The report cites 10 potential obesity risk factors in all, including: increased rates of older mothers, whose children may be more prone to excess weight gain; a range of medications, such as antidepressants, which can promote weight gain; and a decrease in smoking rates, because people often gain weight when they quit and the absence of nicotine, an appetite suppressant. No one is suggesting that people should stop taking their prescriptions, keep smoking or swelter in the July sun, according to the researcher Allison. When it comes to any one person's weight, he said, "what ultimately matters is calorie intake and calorie expenditure."

本周二公布的一项调查显示：美国人不能把肥胖问题完全归咎于快餐饮食和长时间看电视。 一个研究小组认为，事实上，现代生活中有很多因素都有可能导致美国人不幸超重，比如睡眠不足和使用空调。 刊登于《国际肥胖期刊》的一份研究报告称，肥胖症研究和预防不能局限于“两大因素”——餐饮业的某些做法，如加大食物的分量或含糖量；运动量减少，如学校取消体育课。 这并不是说饮食和运动不重要，无论怎样，肥胖是否直接跟饮食业的市场策略和缺少体育课有关系得视情况而言。 研究人员指出：睡眠不足也是诱发肥胖的一大因素。通过对动物和人体的研究发现，长期缺乏睡眠会刺激食欲。研究同时显示，美国成年人和儿童目前的睡眠时间比过去少。近几十年，成年人每天平均睡眠时间由过去的9小时降至7小时。 另一个诱发美国人肥胖焦虑的潜在因素是空调。当体温自动进行调节时，身体会消耗热量，同时，湿热的天气会让人们减少食量。 研究报告列举了诱发肥胖的十大因素：大龄妈妈比例增加，她们的后代可能更容易超重；一些药物会导致体重超标，如抗抑郁病药；烟民比例减少——尼古丁有抑制食欲的作用，所以吸烟者一旦戒烟会导致体重增加。 据研究人员艾利森介绍，这项研究并不是建议人们停止使用药方、继续吸烟或忍受炎暑的折磨。当谈到个人的体重问题时，艾利森说，“最重要的还是看你摄取和消耗了多少热量。”