Conventional wisdom about diets, including government health recommendations, seems to change all the time.
人们对饮食的普遍看法，包括政府的健康推荐，似乎永远都在发生变化。
And yet, ads routinely come about claiming to have the answer about what we should eat.
然而广告却一如既往地声称，他们能够回答我们应该吃什么这个问题。
So how do we distinguish what's actually healthy from what advertisers just want us to believe is good for us?
所以我们如何才能从广告商们想让我们相信对我们有好处的东西中，辨别出真正健康的食物呢？
Marketing takes advantage of the desire to drop weight fast, and be stronger, slimmer, and brighter.
营销人员利用了我们想要快速减重，变得更强壮、更纤细、气色更好的心愿。
And in the big picture, diet plans promising dramatic results, known as fad diets,
大体来看，那些承诺会有显著效果的饮食计划，即流行饮食法，
are just what they seem: too good to be true.
和它们的外表一模一样：太过美好而不真实。
So where do diet fads even come from?
那么，膳食风尚究竟来自何处？
While the Ancient Greeks and Romans rallied behind large-scale health regimens centuries earlier,
几个世纪之前，在古希腊人和古罗马人一致支持大规模的健康养生法时，
this phenomenon began in earnest in the Victorian Era with crazes like the vinegar diet and the Banting Diet.
这种现象在维多利亚时期正式形成，这期间出现了像喝醋减肥和节食减肥这样的热潮。
Since then, diets have advised us all sorts of things: to excessively chew, to not chew at all,
自那以后，饮食规定给我们提供了各种建议，比如要多咀嚼，不要咀嚼，
to swallow a grapefruit per meal, non-stop cabbage soup, even consumption of arsenic, or tapeworms.
每顿饭吃一个葡萄柚，不停地喝卷心菜汤，甚至食用砒霜或者绦虫。
If the idea of diet crazes has withstood history, could this mean that they work?
如果这些饮食热潮中提出的想法经受住了历史的检验，那这是不是就说明它们是有效的？
In the short term, the answer is often yes.
短期来看，答案往往是肯定的。
Low-carbohydrate plans, like the popular Atkins or South Beach Diets, have an initial diuretic effect.
碳水化合物含量低的植物，比如流行的阿金饮食法或迈阿密饮食法，都有初步的利尿效果。
Sodium is lost until the body can balance itself out, and temporary fluid weight loss may occur.
在身体能够补充之前，我们流失了钠元素，而且还会出现体液流失造成的暂时体重下降。
With other high-protein diets, you might lose weight at first since by restricting your food choices,
使用其他高蛋白的饮食法时，也许早期由于控制了食物选择，你的体重会有所下降，
you are dropping your overall calorie intake.
你在减少你的整体卡路里摄入。
But your body then lowers its metabolic rate to adjust to the shift,
但是稍后你的身体会降低代谢速率以适应这种转变，
lessening the diet's effect over time and resulting in a quick reversal if the diet is abandoned.
节食的效果也会就此渐渐减轻，并且放弃这种饮食法后会导致快速反弹。
So while these diets may be alluring early on, they don't guarantee long-term benefits for your health and weight.
所以，虽然这些饮食法早期也许非常诱人，但它们不能保证对你的健康和体重有长期的好处。
A few simple guidelines, though, can help differentiate between a diet that is beneficial in maintaining long-term health,
不过，有一些简单的准则可以帮你将有利于保持长期健康的饮食法
and one that only offers temporary weight changes.
和只能带来暂时体重变化的区别开来。

Here's the first tip-off: if a diet focuses on intensely cutting back calories or on cutting out entire food groups,
第一条提示：如果一个饮食法密切关注减少卡路里或者排除整个食物群，
like fat, sugar, or carbohydrates, chances are it's a fad diet.
像脂肪、糖或碳水化合物，那它很有可能就是一个流行饮食法而已。
And another red flag is ritual, when the diet in question instructs you to only eat specific foods,
另一个危险信号是惯例，也就是存疑的这个饮食法指导你只食用特定的食物，
prescribed combinations, or to opt for particular food substitutes, like drinks, bars, or powders.
规定的搭配，或者选择特定的食物替代品，比如饮品、能量棒或粉末。
The truth is shedding pounds in the long run simply doesn't have a quick-fix solution.
真相是，长期减重并没有捷径可走。
Not all diet crazes tout weight loss.
并不是所有的饮食法都标榜减重。
What about claims of super foods, cleanses, and other body-boosting solutions?
那些号称超级食物、身体净化剂和其他强身健体的方案怎么样呢？
Marketing emphasizes the allure of products associated with ancient and remote cultures
营销人员强调这些和远古文化有关的产品的吸引力，
to create a sense of mysticism for consumers.
来给消费者带来一种神秘的感觉。
While so-called super foods, like blueberries or acai, do add a powerful punch of nutrients,
虽然所谓的超级食物，比如蓝莓和巴西莓确实能大量增加营养，
their super transformative qualities are largely exaggeration.
但它们带来超级蜕变的能力被过度夸大了。
They are healthy additions to a balanced diet, yet often, they're marketed as part of sugary drinks or cereals,
它们确实是一个均衡膳食中健康的补充物，但是它们往往被作为一种含糖饮料或麦片兜售，
in which case the negative properties outweigh the benefits.
而这种情况下，它们的负面效果远远超过了好处。
Cleanses, too, may be great in moderation since they can assist with jump-starting weight loss
身体净化剂也是如此，由于它们在减重方面能起到助力作用，
and can increase the number of fresh fruits and vegetables consumed daily.
而且可以增加每日摄入的新鲜水果和蔬菜数量，它们在调理方面也许作用强大。
Scientifically speaking, though, they've not yet been shown to have either a long-term benefit
但是，从科学的角度来说，它们尚未被证明有长期好处，
or to detox the body any better than the natural mechanisms already in place.
而且在给身体排毒方面也不见得就比已经存在的天然机制要好。
Everywhere we look, we're offered solutions to how we can look better, feel fitter, and generally get ahead. Food is no exception,
在我们目光所及之处都能找到告诉我们怎样才能看起来更好、感觉更健康、总体领先的方案。食物也不例外，
but advice on what we should eat is best left to the doctors and nutritionists who are aware of our individual circumstances.
但是饮食方面的建议最好还是交给了解我们个人状况的医生和营养师吧。
Diets and food fads aren't inherently wrong.
饮食法和膳食风尚不一定都是错的。
Circumstantially, they might even be right, just not for everyone all of the time.
在特定情况下，它们甚至也许是正确的，只不过并不是一直适用于我们所有人。