译言

Ask anyone why there is an obesity epidemic and they will tell you that it’s all down to eating too much and burning too few calories. That explanation appeals to common sense and has dominated efforts to get to the root of the obesity epidemic and reverse it/ yet obesity researchers are increasingly dissatisfied with it. Many now believe that something else must have changed in our environment to precipitate(促成) such dramatic rises in obesity over the past 40 years or so. Nobody is saying that the “big two” – reduced physical activity and increased availability of food – are not important contributors to the epidemic, but they cannot explain it all.

Earlier this year a review paper by 20 obesity experts set out the 7 most plausible alternative explanations for the epidemic. Here they are.

　　随便找人问问，肥胖症为什么会如此流行，他们都会告诉你，那是因为吃得太多而消耗的热量太少。这是广为认可的解释，这种解释促使人们努力寻求肥胖的根源，并试图证 明它（尽管肥胖症研究者对这一解释越来越不满意）。一些研究人员认为是由于某些环境改变造成了40年来肥胖的剧烈增长。没人否认，减少体育活动和暴饮暴食对肥胖症贡献 巨大，可没人能够解释其更多的成因。今年早些时候20名肥胖症专家在一篇论文里列举了七项令人肥胖的解释。内容如下：

　　1. Not enough sleep

　　1、睡眠不足

　　It is widely believed that sleep is for the brain, not the body. Could a shortage of shut-eye also be helping to make us fat?

　　人们普遍相信睡眠对脑部有影响，而对身体没有影响。缺乏睡眠也会让我们变胖吗？

　　Several large-scale studies suggest there may be a link. People who sleep less than 7 hours a night tend to have a higher body mass index than people who sleep more, according to data gathered by the US National Health and Nutrition Examination Survey. Similarly, the US Nurses’ Health Study, which tracked 68,000 women for 16 years, found that those who slept an average of 5 hours a night gained more weight during the study period than women who slept 6 hours, who in turn gained more than whose who slept 7.

　　很多大范围的研究认为它们之间是有联系的。根据美国国家健康与营养调查中心收集来的数据，睡眠不足7小时的人有很大几率比睡眠充足的人更容易变得肥胖。类似还有美 国健康护理研究中心得来的数据，根据对68000名16岁女性的数据追踪，发现晚上平均睡眠5小时的人比平均睡眠6小时的女性出现肥胖问题，同理6小时女性群体比7小 时群体更容易胖些。

　　It’s well known that obesity impairs sleep, so perhaps people get fat first and sleep less afterwards. But the nurses’ study suggests that it can work in the other direction too: sleep loss may precipitate weight gain.

　　众所周知肥胖的人会睡不好，但也可能该反过来看待睡眠不足与变胖的关系。护理中心的研究认为从另一个角度来看：睡眠不足可能预示着体重将增加。

　　Although getting figures is difficult, it appears that we really are sleeping less. In 1960 people in the US slept an average of 8.5 hours per night. A 2002 poll by the National Sleep Foundation suggests that the average has fallen to under 7 hours, and the decline is mirrored by the increase in obesity.

　　尽管得出精确的数据挂钩显得很困难，但这些数据显示出我们的睡眠正在减少。1960年美国人晚上平均睡眠8.5小时。2002年根据国家睡眠基金会的调查显示，平 均夜间睡眠降到了7小时以下，与之呼应的倾向是人们的肥胖状况有所增加。

　　2. Climate control

　　2、天气控制

　　We humans, like all warm-blooded animals, can keep our core body temperatures pretty much constant regardless of what’s going on in the world around us. We do this by altering our metabolic(新陈代新的) rate, shivering or sweating. Keeping warm and staying cool take energy unless we are in the “thermo-neutral zone”, which is increasingly where we choose to live and work.

　　人类是恒温动物，无论在什么样的环境下，可以保持我们的核心体温相对恒定。人类通过发抖或是流汗，改变体内的新陈代谢率来做到这一点。只有处在“热中性区（是环境 的温度范围，在这个温度范围内，内温动物仅使用一 个最小的代谢率以维持恒定的体温）”我们才能保持身子适宜，易于摄取能量，越来越多人选择在这样的环境下生活和工作。

　　There is no denying that ambient temperatures(环境温度) have changed in the past few decades. Between 1970 and 2000, the average British home warmed from a chilly 13C to 18C. In the US, the changes have been at the other end of the thermometer as the proportion of homes with air conditionings rose from 23% to 47% between 1978 and 1997. In the southern states – where obesity rates tend to be highest – the number of houses with air conditioning has shot up to 71% from 37% in 1978.

　　 不容否定，过去数十年间环境温度有所改变。1970年到2000年，英国的平均人居环境温度从13摄氏度变成了18摄氏度。在美国，这一改变从另一方面显示了出 来，从1978到1997，美国选择“温度与空气调节系统房屋”的比例从23%升至了47%。美国南部州的肥胖率变得最高，因为自1978年以来，这部分地区入住空调 系统房的比例从71%降到了37%。

　　Could air conditioning in summer and heating in winter really make a difference to our weight?

　　冬暖夏凉的空调系统能对我们的体重造成差异吗？

　　Sadly，there is some evidence that it does-at least with regard to heating. Studies show that in comfortable temperatures we use less energy.

　　不幸的是，有些证据显示至少“温度”对人的体重的确会有影响。调查显示，在适宜居住的环境温度下，人体的能量消耗会变得更少。

　　3.Less smoking

　　3、少抽烟

　　Bad news: smokers really do tend to be thinner than the rest of us,and quitting really does pack on the pounds, though no one isn sure why. It probably has something to do with the fact that nicotine is an appetite suppressant and appears to up your metabolic rate.

　　坏消息：吸烟者的确比不吸烟的人显得苗条，而戒烟者容易增加体重，尽管无人知其原因。尼古丁可能是一种食欲抑制剂，会提升人体的新陈代谢比率。

　　Katherine Flegal and colleagues at the US National Center for Health Statistics in Hyattsville,Maryland, have calculated that people kicking the habit have been responsible for a small but significant portion of the US epidemic of fatness.From data collected aroud 1991 by the US National Health and Nutrition Examination Survey,they worked out that people who had quit in the previous decade were much more likely to be overweight than smokers and people who had never smoked .Among men, for example, nearly half of quitters were overweight compared with 37% of non-smokers and only 28%of smokers.

　　凯瑟琳·弗莱格尔与马里兰州海厄茨维尔美国国家卫生统计中心的同事计算得出， 戒烟者在美国肥胖症流行的成因中占有不大但也很重要的比例。从1991收集来 的数据（出自美国健康与营养调查中心），他们发现比起吸烟者和从来不吸烟的人，过去十年内戒掉烟瘾的人超重的可能性要大得多。举例来说，戒烟者有将近一半人超重，而不吸烟的人只有37%、吸烟者只有28%超重。

　　4. Genetic effects

　　4、遗传效应

　　Yours chances of becoming fat may be set,at least in part,before you were even born.children of obese mothers are much more likely to become obest themselves later in life.Offspring of mice fed a high-fat diet during pregnancy are much more likely to become fat than the offspring of identical mice fed a normal diet. Intriguingly,the effect persists for two or three generations.Grand-children of mice fed a high-fat diet grow up fat even if their own mother is fed normally-so you fat may have been sealed even before you were conceived.

　　你变胖的几率一部分在你出生时就已经决定了。胖妈妈的孩子未来可能会变得和她一样。相对喂食普通食物的老鼠妈妈，喂食高脂肪食物的老鼠妈妈生下的后代有可能会变得 更胖。有趣的是，这样的效果会出现在两三代之后。符合祖母习惯的孙儿辈老鼠，只要吃了高脂肪食物就有可能快速变胖，即便它的母亲体重正常——因此你的肥胖在你这辈子前 就已经决定了。

　　5.A little older…

　　5、年龄增长……

　　Some groups of people just happen to be fatter than others.surveys carried out by the US national center for health statisties found that adults aged 40 to 79 were around three times as likely to be obese as younger people.non- white females also tend to fall at the fatter end of the spectrum:Mexican- american women are 30% more likely than white women to be obsess,and black women have twice the risk.

　　有一类人就是比别的人更容易胖。美国国家健康中心的数据统计发现，40到79岁的人肥胖率是年轻人的3倍。非白人女性是最容易变胖的：其中超出30%的墨裔美国人 （女性）比白人（妇女）更容易受到肥胖症的困扰，黑人女性的风险更大一倍（超出60%的白人女性）。

　　In the US,these groups account for an increasing percentage of the population.between 1970 and 2000 the US population aged 35 to 44 grew by 43%.the proportion of Hispanic-americans also grew,from under 5% to 12.5% of the population,while the proportion of black Americans increased from 11% to 12.3%.these changes may account in part for the increased prevalence of obesity.

　　 在美国，这些人群中的肥胖比例不断增大。1979到2000年，35到44岁的美国人肥胖人口增长了43%。拉美裔的肥胖比例也在增长，从5%增到了12.5% 。而美国黑人的肥胖比例从11%上升到12.3%。这些变化可能部分导致了肥胖患病的几率。

　　 6.mature mums

　　 6、成熟母亲

　　Mothers around the world are getting older.in the UK,the mean age for aging a frist child is 27.3,compared with 23.7 in 1970 .mean age at frist birth in the US has also increased, rising from 21.4 in 1970 to 24.9 in 2000.

　　 全世界的母亲更为高龄化。在英国，生第一胎母亲的平均年龄是27.3岁。相比之下，在1970年，这个数字为23.7岁。美国生第一胎母亲的平均年龄也在增长， 1970年时平均年龄为21.4岁，到2000年变成了24.9岁。

　　This would be neither here nor there if it were’t for the observation that having an older mother seems to be an independent risk factor for obesity. Results from the US national heart,lung and blood institute’s study found that the odds of a child being obese increase 14% for every five extra years of their mother’s age , though why this should be so is not entirely clear.

　　 这并不是袖手旁观就能够解决的问题，如果我们不为这些高龄女性做点什么的话，肥胖将成为她们独立的一个危险因素。来自美国国家心、肺、血液研究所的研究发现，初 孕母亲的年龄每长5年，生出孩子的肥胖风险多出14%（与年龄相差5年的母亲后代相比）。

　　Michael Symonds at the university of Nottingham,UK,found that first-bron children have more fat than younger ones. As family size decreases, firstbrons account for a greather share of the population. In 1964, british women gave birth to an average of 2.95 children;by 2005 that figure had fallen to 1.79. in the US in 1976, 9.6% of woman in their 40s had only one chile;in 2004 it was 17.4%. this combination of older mothers and more single children could be contributing to the obesity epidemic.

　　 美国诺丁汉大学的迈克尔·西蒙兹发现，长子长女比其它子女有更多的脂肪。随着家庭规模的减少，初胎子女带来的肥胖危害比例就越大。1964年，英国女性平均生育 2.95个孩子；2005年数字降到了1.79。在1976年的美国，9.6%的40岁女性只有一个孩子；到了2004年，17.4%的40岁女性拥有一个孩子。这种 高龄母亲与独生子女的组合，有可能会导致肥胖病。

　　7.Like marrying like

　　7、同类婚嫁

　　Just as people pair off according to looks, so they do for size. Lean people are more likely to marry lean and fat more likely to marry fat. On its own, like marrying like cannot account for any increase in obesity. But combined with others- particularly the fact that obesity is partly genetic, and that heavier people have more children-it amplifies the increase form other causes.

　　如同人们对于外表的相互吸引，体重也是一样。瘦子更愿意和瘦子结婚，胖子愿意选择胖子。就结婚本身而言，婚姻看来不应该背上导致肥胖的黑锅。但综合别的因素来看， 尤其是基于肥胖遗传的影响，越胖的夫妇生下越多的后代，意味着这将是社会肥胖症的成因之一。