当你节食时，你的身体是如何反击的？

当你节食时，你的身体是如何反击的？

Diets do not work.

节食不起作用。

The scientific evidence is clear as can be that cutting calories simply doesn't lead to long-term weight loss or health gains.

科学证据很清楚，减少热量摄入并不会导致长期的体重减轻或健康状况改善。

We suspect most dieters have realized this by now too. And yet, here they are again, setting the same weight loss goal this year that they set last year.

我们怀疑大多数节食者现在也意识到了这一点。然而，他们又一次制定了和去年一样的减肥目标。

The only people who don't seem to appreciate this are people who have never dieted. It's particularly hard for them to believe because it doesn't square with their own eating experiences.

似乎只有从未节食的人才不明白这一点。尤其让他们难以置信的是，这与他们自己的饮食经历不符。

Take Nicky, for instance. She eats sensibly much of the time, with some junk food here and there, but it doesn't really seem to affect her weight. She's not a dieter. She is naturally thin , and it's not surprising that she believes what she sees with her own eyes and feels in her own body. Nevertheless, Nicky has it wrong.

以尼基为例。她大部分时间都吃得很理智，偶尔吃点垃圾食品，但这似乎并没有真正影响她的体重。她不是节食者。她天生就很瘦，所以她相信自己的眼睛和身体的感觉也就不足为奇了。然而，尼基错了。

We are researchers who have been studying why diets fail for a long time. We have seen that diet failure is the norm. We have also studied the stigma that heavy people face, and witnessed the blame game that happens when dieters can't keep the weight off. From a scientific perspective, we understand that dieting sets up an unfair fight. But many Nickys we've encountered -- on the street, in the audience when we give talks, and even fellow scientists -- get confused when we say dieting doesn't work, because it doesn't square with their own observations.

我们这些研究人员长期以来一直在研究为什么节食会失败。我们已经看到节食失败是一种常态。我们还研究了体重超标的人所面临的耻辱，并目睹了节食者无法保持体重时所发生的指责。从科学的角度来看，我们明白节食会引发一场不公平的斗争。但是我们遇到的许多尼基人——在街上，在我们演讲的时候的听众中，甚至是我们的科学家同行——当我们说节食不起作用时，他们会感到困惑，因为这与他们自己的观察不相符。

An unfair fight

一个不公平的抗争

Nicky thinks she's thin because of the way she eats, but actually, genetics play a huge role in making her thin. Nicky gets all the credit though, because people see the way she eats and they can't see her genes.

尼基认为她瘦是因为她吃东西的方式，但实际上，基因在使她瘦的过程中发挥了巨大的作用。尼基得到了所有的赞誉，因为人们看到了她的饮食方式，却看不到她的基因。

Many heavy people wouldn't be lean like Nicky even if they ate the same foods in the same quantities. Their bodies are able to run on fewer calories than Nicky's, which sounds like a good thing (and would be great if you found yourself in a famine).

许多肥胖的人不会像尼基一样瘦，即使他们吃同样数量的食物。他们的身体比尼基的消耗更少的卡路里，这听起来像是一件好事(如果你发现自己陷入了饥荒，那就太好了)。

However, it actually means that after eating the same foods and using that energy to run the systems of their body, they have more calories left over to store as fat than Nicky does. So to actually lose weight, they have to eat less food than Nicky. And then, once they've been dieting a while, their metabolism changes so that they need to eat even less than that to keep losing weight.

然而，这实际上意味着，在吃了同样的食物，并利用这些能量来运行身体系统之后，他们比尼基有更多的卡路里作为脂肪储存起来。所以，为了真正减肥，他们必须比尼基吃更少的食物。然后，一旦他们节食了一段时间，他们的新陈代谢就会发生变化，所以他们需要吃得更少才能持续减肥。

It's not just Nicky's genetically given metabolism that makes her think dieting must work. Nicky, as a non-dieter, finds it really easy to ignore that bowl of Hershey's Kisses on her co-worker's desk. But for dieters, it's like those Kisses are jumping up and down saying "Eat me!" Dieting causes neurological changesthat make you more likely to notice food than before dieting, and once you notice it, these changes make it hard to stop thinking about it. Nicky might forget those chocolates are there, but dieters won't.

尼基认为节食必须奏效，并不仅仅是因为基因决定的新陈代谢。尼基是个非节食者，她发现自己很容易忽视同事桌上那碗好时(Hershey)的热吻。但对于减肥者来说，这就像那些吻跳上跳下说“吃了我!”节食会引起神经系统的变化，使你比节食前更容易注意到食物，一旦你注意到了，这些变化就会使你很难停止思考。尼基可能会忘记巧克力的存在，但节食者不会。