Why dieting doesn't usually work | Sandra Aamodt

譯者: Lyman Zhang 審譯者: Shiwen He

Three and a half years ago,

三年半前，

I made one of the best decisions of my life.

我做了一個人生中最正確的決定。

As my New Year's resolution,

過年要有新決心

I gave up dieting, stopped worrying about my weight,

我決定放棄減肥，不再擔心自己的體重

and learned to eat mindfully.

而是吃東西的時候留心一些

Now I eat whenever I'm hungry,

現在，我餓了就吃飯

and I've lost 10 pounds.

而且我已經減掉了10磅（4.5公斤）

This was me at age 13,

這是十三歲的我，第一次減肥

when I started my first diet.

這是十三歲的我，第一次減肥

I look at that picture now, and I think,

現在看著這張照片，我會想

you did not need a diet,

“你不需要減肥”

you needed a fashion consult.

“你倒該去找個時尚顧問…”

(Laughter)

（笑）

But I thought I needed to lose weight,

但當時我認為自己需要減肥， 當減掉的體重又回來之後

and when I gained it back,

但當時我認為自己需要減肥， 當減掉的體重又回來之後

of course I blamed myself.

我全都怪在自己身上。

And for the next three decades,

在接下來的三十多年裡，

I was on and off various diets.

我一次次地嘗試各種減肥法。

No matter what I tried,

不管我怎麼做， 減掉的重量最後總是長回來。

the weight I'd lost always came back.

不管我怎麼做， 減掉的重量最後總是長回來。

I'm sure many of you know the feeling.

肯定有不少人理解這種感覺。

As a neuroscientist,

作為一個神經學家，

I wondered, why is this so hard?

我很好奇為什麼減肥如此困難？

Obviously, how much you weigh depends on

很明顯，體重取決於 “吃多少食物”和“消耗多少能量”

how much you eat and how much energy you burn.

很明顯，體重取決於 “吃多少食物”和“消耗多少能量”

What most people don't realize

而大多數人沒有意識到，

is that hunger and energy use

飢餓感和能量的消耗，是由大腦控制的。

are controlled by the brain,

飢餓感和能量的消耗，是由大腦控制的。

mostly without your awareness.

而基本上和意識無關。

Your brain does a lot of its work behind the scenes,

大腦把很多事情放在“幕後”自動處理，

and that is a good thing,

這是好事，因為你的“意識”──

because your conscious mind --

這是好事，因為你的“意識”──

how do we put this politely? --

──怎麼把話說得好聽點呢？──

it's easily distracted.

注意力很容易分散。

It's good that you don't have to remember to breathe

比如看電影的時候， 你不用怕自己忘記呼吸怎麼辦。

when you get caught up in a movie.

比如看電影的時候， 你不用怕自己忘記呼吸怎麼辦。

You don't forget how to walk

在考慮晚餐吃什麼的時候， 你不會忘了怎麼走路。

because you're thinking about what to have for dinner.

在考慮晚餐吃什麼的時候， 你不會忘了怎麼走路。

Your brain also has its own sense

大腦對體重也有自己的一套想法，

of what you should weigh,

大腦對體重也有自己的一套想法，

no matter what you consciously believe.

不論你的“意識”是怎麼想的。

This is called your set point,

這被稱為你的“固定值“，

but that's a misleading term,

但這個名字有點誤導視聽，

because it's actually a range

準確來說，這個數值 可以自由浮動約10﹣15磅（約5-7kg）

of about 10 or 15 pounds.

準確來說，這個數值 可以自由浮動約10﹣15磅（約5-7kg）

You can use lifestyle choices to move your weight

生活方式的改變， 會在這個範圍內影響你的體重。

up and down within that range,

生活方式的改變， 會在這個範圍內影響你的體重。

but it's much, much harder to stay outside of it.

但想在這個範圍以外，就非常困難了。

The hypothalamus, the part of the brain

在下丘腦，你大腦調節體重的部份，

that regulates body weight,

在下丘腦，你大腦調節體重的部份，

there are more than a dozen chemical signals

有十多種化學信號控制著”體重的增加“，

in the brain that tell your body to gain weight,

有十多種化學信號控制著”體重的增加“，

more than another dozen that tell your body to lose it,

另外還有十多種化學信號， 控制著”體重的減少“。

and the system works like a thermostat,

這整個系統就像是個恒溫器，

responding to signals from the body

對身體的刺激作出反應，

by adjusting hunger, activity and metabolism,

調整飢餓感，活動量和新陳代謝，

to keep your weight stable as conditions change.

在不同環境下，維持你的體重。

That's what a thermostat does, right?

恒溫器就是這樣工作的，不是麼？

It keeps the temperature in your house the same

恒溫器確保室內溫度 總是保持在一定範圍內

as the weather changes outside.

不管外面的天氣怎麼變化。

Now you can try to change the temperature

你可以在冬天打開窗戶，來調節室內溫度，

in your house by opening a window in the winter,

你可以在冬天打開窗戶，來調節室內溫度，

but that's not going to change the setting on the thermostat,

但這不會改變恒溫器的設定。

which will respond by kicking on the furnace

於是它做出反應，啟動暖爐加熱整個房間。

to warm the place back up.

於是它做出反應，啟動暖爐加熱整個房間。

Your brain works exactly the same way,

減肥的時候，你的大腦也會做出一樣的反應，

responding to weight loss by using powerful tools

減肥的時候，你的大腦也會做出一樣的反應，

to push your body back

用非常規的手段， 把身體調整到”它“認為合適的狀態。

to what it considers normal.

用非常規的手段， 把身體調整到”它“認為合適的狀態。

If you lose a lot of weight,

如果你一口氣減掉很多重量，

your brain reacts as if you were starving,

你的大腦會認為你快餓死了，

and whether you started out fat or thin,

不論一開始是胖是瘦，大腦的反應都是一樣的。

your brain's response is exactly the same.

不論一開始是胖是瘦，大腦的反應都是一樣的。

We would love to think that your brain could tell

我們當然希望大腦 可以判斷本人是否想要減肥

whether you need to lose weight or not,

我們當然希望 大腦可以判斷本人是否想要減肥

but it can't.

但它辦不到。

If you do lose a lot of weight,

如果你一口氣減掉很多，

you become hungry,

你會感到飢餓，

and your muscles burn less energy.

你的肌肉消耗的能量也一起下降。

Dr. Rudy Leibel of Columbia University

哥倫比亞大學的Rudy Leibel教授

has found that people who have lost

發現那些減少過10％體重的人，

10 percent of their body weight

發現那些減少過10％體重的人，

burn 250 to 400 calories less

每天少消耗250﹣400卡路里

because their metabolism is suppressed.

因為他們的新陳代謝被壓抑了。

That's a lot of food.

那相當於一頓大餐了。

This means that a successful dieter

這就是說，減肥成功的人

must eat this much less forever

必須從此以後每天少吃這麼一頓大餐

than someone of the same weight

才能趕上那些不用減肥， 也一直是這個體重的人。

who has always been thin.

才能趕上那些不用減肥， 也一直是這個體重的人。

From an evolutionary perspective,

從進化的角度來說，

your body's resistance to weight loss makes sense.

身體對於”減肥“的抵抗性是有理由的。

When food was scarce, our ancestors' survival

因為我們的祖先， 在食物匱乏的時候必須節約體能，

depended on conserving energy,

因為我們的祖先， 在食物匱乏的時候必須節約體能，

and regaining the weight when food was available

而在食物充沛時儘快補回失去的分量，

would have protected them against the next shortage.

才能抵禦下一次饑荒。

Over the course of human history,

縱觀歷史，

starvation has been a much bigger problem

食物短缺一直比超重要嚴重得多。

than overeating.

食物短缺一直比超重要嚴重得多。

This may explain a very sad fact:

這解釋了一個令人難過的事實：

Set points can go up,

體重的”固定值“可能上升，

but they rarely go down.

但幾乎不會下降。

Now, if your mother ever mentioned

如果媽媽曾經告訴你們，

that life is not fair,

世上有很多不公平的事，

this is the kind of thing she was talking about.

這肯定就是其中之一了。（笑）

(Laughter)

這肯定就是其中之一了。（笑）

Successful dieting doesn't lower your set point.

減肥成功不會降低你的”固定值“。

Even after you've kept the weight off

就算你保持體重減輕整整七年

for as long as seven years,

就算你保持體重減輕整整七年

your brain keeps trying to make you gain it back.

你的大腦也依然會試圖把體重增回來。

If that weight loss had been due to a long famine,

如果體重減輕是因為長期饑荒

that would be a sensible response.

那這種反應也無可厚非。

In our modern world of drive-thru burgers,

而在快餐橫行的現代社會，

it's not working out so well for many of us.

這套反應機制就不太妙了。

That difference between our ancestral past

古老的過去，和富足的現代之間的差別

and our abundant present

古老的過去，和富足的現代之間的差別

is the reason that Dr. Yoni Freedhoff

正是渥太華大學的Yoni Freedhoff博士

of the University of Ottawa

為什麼會開玩笑說，

would like to take some of his patients back to a time

他想把一些病人送回食物不充足的時代， （“給我一台時光機， 我就給你全世界最好的減肥計劃”）

when food was less available,

他想把一些病人送回食物不充足的時代， （“給我一台時光機， 我就給你全世界最好的減肥計劃”）

and it's also the reason

他想把一些病人送回食物不充足的時代， （“給我一台時光機， 我就給你全世界最好的減肥計劃”）

that changing the food environment

這也是為什麼，飲食環境的改變 才是應對肥胖最有效的措施。

is really going to be the most effective solution

這也是為什麼，飲食環境的改變 才是應對肥胖最有效的措施。

to obesity.

這也是為什麼，飲食環境的改變 才是應對肥胖最有效的措施。

Sadly, a temporary weight gain

可惜的是，一時的增重，

can become permanent.

可能變成永久的增重。

If you stay at a high weight for too long,

如果超重的狀態保持太久，

probably a matter of years for most of us,

對大多數人大概幾年左右，

your brain may decide that that's the new normal.

你的大腦可能會決定說，那才是新的”固定值“。

Psychologists classify eaters into two groups,

心理學家把”吃貨“分為兩類：

those who rely on their hunger

一種是餓了就吃

and those who try to control their eating

一種是試圖控制飲食， 也就是大部份減肥者的做法。

through willpower, like most dieters.

一種是試圖控制飲食， 也就是大部份減肥者的做法。

Let's call them intuitive eaters and controlled eaters.

我們就叫他們”想吃就吃“和”自控地吃“吧。

The interesting thing is that intuitive eaters

有意思的是，”想吃就吃“的人

are less likely to be overweight,

比較不容易超重，

and they spend less time thinking about food.

這些人也不太去想吃的事。

Controlled eaters are more vulnerable

自控的吃貨，反而容易受到諸如

to overeating in response to advertising,

廣告宣傳、超大分量、無限量自助餐 之類的誘惑和影響。

super-sizing, and the all-you-can-eat buffet.

廣告宣傳、超大分量、無限量自助餐 之類的誘惑和影響。

And a small indulgence,

小小的誘惑，

like eating one scoop of ice cream,

比如一勺冰淇淋，

is more likely to lead to a food binge

更容易引起”自控型“的人去暴飲暴食。

in controlled eaters.

更容易引起”自控型“的人去暴飲暴食。

Children are especially vulnerable

青少年尤其容易陷入”減肥後暴食“的循環。

to this cycle of dieting and then binging.

青少年尤其容易陷入”減肥後暴食“的循環。

Several long-term studies have shown

一些長期調查研究顯示，

that girls who diet in their early teenage years

十幾歲時減過肥的女孩，

are three times more likely to become overweight

五年後超重的概率是普通人的三倍，

five years later,

五年後超重的概率是普通人的三倍，

even if they started at a normal weight,

就算她們一開始時體重正常，

and all of these studies found

所有這些研究都顯示

that the same factors

一些因素在預測了超重的同時

that predicted weight gain

一些因素在預測了超重的同時

also predicted the development of eating disorders.

也預測了”飲食障礙“。

The other factor, by the way,

另一個因素，順帶一提，

those of you who are parents,

請家長們注意了，

was being teased by family members

是”被家庭成員嘲笑體重“這件事。

about their weight.

是”被家庭成員嘲笑體重“這件事。

So don't do that.

所以拜託，

(Laughter)

別這麼做了。（笑）

I left almost all my graphs at home,

我幾乎把圖表都留在家裡了，

but I couldn't resist throwing in just this one,

不過我忍不住要給你們看這張圖，

because I'm a geek, and that's how I roll.

因為我是個書蟲，沒圖表不舒服。（笑）

(Laughter)

因為我是個書蟲，沒圖表不舒服。（笑）

This is a study that looked at the risk of death

這是一個持續了十四年

over a 14-year period

關於健康風險的研究

based on four healthy habits:

通過觀察平時的四個健康習慣：

eating enough fruits and vegetables,

攝入足夠的蔬果，

exercise three times a week,

每週運動三次，

not smoking,

不吸菸，

and drinking in moderation.

適度飲酒。

Let's start by looking at the normal weight

我們先來看一看正常體重的人群吧

people in the study.

我們先來看一看正常體重的人群吧

The height of the bars is the risk of death,

柱子的高度，代表死亡率

and those zero, one, two, three, four numbers

橫軸的0,1,2,3,4

on the horizontal axis

橫軸的0,1,2,3,4

are the number of those healthy habits

代表研究對象有幾個健康習慣

that a given person had.

代表研究對象有幾個健康習慣

And as you'd expect, the healthier the lifestyle,

你能猜得到，生活方式越健康，

the less likely people were to die during the study.

人的死亡率也越低。

Now let's look at what happens

接著來看一下

in overweight people.

超重的人的數據。

The ones that had no healthy habits

那些完全沒有健康習慣的人，

had a higher risk of death.

死亡率比較高。

Adding just one healthy habit

僅僅是多了一個健康的習慣

pulls overweight people back into the normal range.

就能把超重的人拉回到普通範圍裡。

For obese people with no healthy habits,

對於沒有任何健康習慣的肥胖者（最右邊）而言，

the risk is very high, seven times higher

死亡風險非常高， 整整比研究中最健康的人高出七倍。

than the healthiest groups in the study.

死亡風險非常高， 整整比研究中最健康的人高出七倍。

But a healthy lifestyle helps obese people too.

但健康的生活方式對肥胖者也有好處。

In fact, if you look only at the group

實際上，如果你光看那些

with all four healthy habits,

四種健康習慣都具備的人，

you can see that weight makes very little difference.

你會發現，是胖是瘦關係不大。

You can take control of your health

如果想要健康的身體

by taking control of your lifestyle,

控制生活習慣就可以了，

even If you can't lose weight

就算你沒辦法減掉體重也沒關係。

and keep it off.

就算你沒辦法減掉體重也沒關係。

Diets don't have very much reliability.

減肥本身就不太可靠。

Five years after a diet,

減肥後的五年內，

most people have regained the weight.

絕大部份人已經反彈了。

Forty percent of them have gained even more.

其中的40％甚至比之前更胖了。

If you think about this,

想想看，

the typical outcome of dieting

就會發現典型的減肥結果，

is that you're more likely to gain weight

更可能是體重增加，而不是減少，

in the long run than to lose it.

就長期而言。

If I've convinced you that dieting

如果我說的讓你信服了

might be a problem,

說減肥可能有壞處

the next question is, what do you do about it?

那麼下一個問題就是，你怎麼辦才好？

And my answer, in a word, is mindfulness.

我的回答，籠統地說，就是”心平氣和”。 （mindfulness也指佛教的“正念”）

I'm not saying you need to learn to meditate

我不是讓你去坐禪冥想，

or take up yoga.

也不是瑜伽。

I'm talking about mindful eating:

我指的是吃東西時留心一點：

learning to understand your body's signals

試著觀察自己身體的信號，

so that you eat when you're hungry

餓了就吃，飽了就停，

and stop when you're full,

餓了就吃，飽了就停，

because a lot of weight gain boils down

因為很多時候體重的增加

to eating when you're not hungry.

是因為明明不餓還要吃。

How do you do it?

具體怎麼做呢？

Give yourself permission to eat

當你餓的時候，允許自己去吃東西，

as much as you want, and then work on figuring out

接著想辦法弄清楚

what makes your body feel good.

怎樣讓身體處於舒適的狀態。

Sit down to regular meals without distractions.

好好專心地坐下吃正餐。

Think about how your body feels

開始吃和停止吃的時候，

when you start to eat and when you stop,

想想看身體的感覺，

and let your hunger decide

讓飢餓感來決定，到哪裡為止。

when you should be done.

讓飢餓感來決定，到哪裡為止。

It took about a year for me to learn this,

掌握這個尺度花了我大概一年的時間，

but it's really been worth it.

不過這很值得。

I am so much more relaxed around food

我不再像以前一樣，

than I have ever been in my life.

現在即使旁邊放著食物，我也能放鬆下來。

I often don't think about it.

我也不太去想吃的事情。

I forget we have chocolate in the house.

我會忘記房間里有塊巧克力。

It's like aliens have taken over my brain.

就好像被外星人控制了我的大腦一樣。（笑）

It's just completely different.

完完全全不一樣了。

I should say that

當然我要說一句，

this approach to eating probably won't make you lose weight

通過這種途徑，基本上不會讓你瘦下來

unless you often eat when you're not hungry,

常常不餓就吃東西那是另一回事。

but doctors don't know of any approach

但是對很多人來說，關於“怎樣才能減輕體重”，

that makes significant weight loss in a lot of people,

醫生也無法給出明確地答案，

and that is why a lot of people are now focusing on

這也是為什麼今天很多人關注的是

preventing weight gain

如果預防肥胖，

instead of promoting weight loss.

而不是到處宣傳減肥。

Let's face it:

面對現實吧：

If diets worked, we'd all be thin already.

要是減肥真的有用，我們早就瘦下來了（笑）

(Laughter)

要是減肥真的有用，我們早就瘦下來了（笑）

Why do we keep doing the same thing

為什麼我們一次又一次做著同樣地事情

and expecting different results?

卻期待不同的結果呢？

Diets may seem harmless,

減肥看似無害，

but they actually do a lot of collateral damage.

但其實附帶了很多傷害

At worst, they ruin lives:

最壞的情況，會損害健康：

Weight obsession leads to eating disorders,

太過執著於體重會導致飲食障礙，

especially in young kids.

特別是青少年人群。

In the U.S., we have 80 percent of 10-year-old girls

在美國，80％的10歲女童

say they've been on a diet.

說自己曾減過肥。

Our daughters have learned to measure their worth

我們的女兒們在 用錯誤的價值觀衡量自己。

by the wrong scale.

我們的女兒們在 用錯誤的價值觀衡量自己。

Even at its best,

即便是最好的情況，

dieting is a waste of time and energy.

減肥也要浪費很多時間和精力。

It takes willpower which you could be using

減肥佔用了意志力 ──這些原本可以用在其他地方──

to help your kids with their homework

比如輔導自己的孩子做功課，

or to finish that important work project,

或者完成重要的工作，

and because willpower is limited,

又因為意志力是有限的，

any strategy that relies on its consistent application

而任何減肥的策略 都會持續地消耗意志力

is pretty much guaranteed

這基本上保證了，

to eventually fail you

一旦注意力轉移到其他地方時

when your attention moves on to something else.

飢餓就會趁虛而入。

Let me leave you with one last thought.

讓我最後再說一點，

What if we told all those dieting girls

如果我們告訴那些減肥中的女孩

that it's okay to eat when they're hungry?

“沒關係的，你想吃的時候就吃” 怎麼樣？

What if we taught them to work with their appetite

如果我們告訴她們，與其害怕自己的胃口

instead of fearing it?

不如學會和它和平相處？

I think most of them would be happier and healthier,

我覺得大部份女孩都會變得更快樂，更健康，

and as adults,

當她們成年後，

many of them would probably be thinner.

不少人可能會變得苗條起來吧。

I wish someone had told me that

我多希望自己十三歲的時候，

back when I was 13.

有人能這樣告訴我。

Thanks.

謝謝。

(Applause)

（鼓掌）