Drink till you drop――喝水也能瘦身

Obesity——肥胖

Drink till you drop——喝水也能瘦身

A magic elixir is shown to promote weight loss ——帮你瘦身的灵丹妙药

Aug 24th 2010 | NEW YORK



CONSUME more water and you will become much healthier, goes an old wives’ tale. Drink a glass of water before meals and you will eat less, goes another. Such prescriptions seem sensible, but they have little rigorous science to back them up.

   有种民间说法广为流传：多喝些水会更健康。还有一种版本是：饭前一杯水，吃饭少一嘴。这些瘦身法听起来挺合情合理，但没有缜密的科学依据。

Until now, that is. A team led by Brenda Davy of Virginia Tech has run the first randomised controlled trial studying the link between water consumption and weight loss. A report on the 12-week trial, published earlier this year, suggested that drinking water before meals does lead to weight loss. At a meeting of the American Chemical Society in Boston this week, Dr Davy unveiled the results of a year-long follow-up study that confirms and expands that finding.
  
  但是现在，这些说法有理有据了。佛吉尼亚科技大学Brenda Davy带领的研究小组率先就饮水与瘦身之间的联系开展了随机对照实验。今年早些时候发表了一份为期12周的实验报告，该实验显示：饭前喝水确实可以减轻体重。在美国化学协会本周于波士顿召开的会议上，Davy博士指出，长达一年的跟踪调查结果支持并拓宽了这个发现。

The researchers divided 48 inactive Americans, aged 55 to 75, into two groups. Members of one were told to drink half a litre of water (a bit more than an American pint) shortly before each of three daily meals. The others were given no instructions on what to drink. Before the trial, all participants had been consuming between 1,800 and 2,200 calories a day. When it began, the women’s daily rations were slashed to 1,200 calories, while the men were allowed 1,500. After three months the group that drank water before meals had lost about 7kg (15½lb) each, while those in the thirsty group lost only 5kg.
  研究员将48位年龄介于55到75岁之间，不爱运动的美国人分为甲乙两组。他们要求甲组成员每日三餐饭前不久喝半升水（500ml）,对乙组成员则没有这方面的要求。实验前，所有的志愿者每天的摄入的热量一直都在1800卡到2200卡之间。实验开始后，女性成员的日常热量摄入量被控制在1200卡，男性成员则被控制在1500卡。三个月后甲组组员每人瘦了7kg，而乙组组员每人只瘦5kg。

Dr Davy confidently bats away some obvious doubts about the results. There is no selection bias, she observes, since this is a randomised trial. It is possible that the water displaced sugary drinks in the hydrated group, but this does not explain the weight loss because the calories associated with any fizzy drinks consumed by the other group had to fall within the daily limits. Moreover, the effect seems to be long-lasting. In the subsequent 12 months the participants have been allowed to eat and drink what they like. Those told to drink water during the trial have, however, stuck with the habit—apparently they like it. Strikingly, they have continued to lose weight (around 700g over the year), whereas the others have put it back on.

  Davy博士信心满满地扫除了对实验结果的一些明显质疑。她指出，这个实验不存在选择性偏差，因为这是一个随机试验。可能甲组组员因为喝了水，就没有再喝加糖饮料了，但这不能解释他们为什么瘦得更多。因为即使乙组组员喝了碳酸饮料，他们每天摄入的卡路里量也是在控制范围内的。况且喝水瘦身的效果似乎是不反弹的。随后的12个月里，志愿者的饮食不再受到限制。然而那些在实验中天天饭前喝水的组员保持了这个习惯，很显然大家喜欢这个习惯。令人吃惊的是，他们的体重还在减轻，一年大约瘦700g，而没喝水的乙组组员的体重却反弹了。

Why this works is obscure. But work it does. It’s cheap. It’s simple. And unlike so much dietary advice, it seems to be enjoyable too.

  这个方法为什么如此有效实在令人费解。但它确实有效，而且便宜、简单，不像其它饮食建议那么繁杂，看起来还那么令人愉快。