So if you burn that amount of flesh, and that sounds kind of, you know, weird, but if you were to convert that into energy, you would get about 3500 Calories, which is quite a lot of energy.

如果你燒掉那塊肉 ，這聽起來是有點怪，但假如你將這塊肉轉化成能量，你就會得到 3500 大卡，這是相當多的能量。

That is me talking with Dr. Carson Chow, an M.I.T. trained physicist and mathematician and he is explaining to me why we should care how much energy fat has.

這是我和趙教授的談話，他是受過麻省理工學院專業訓練的物理學家和數學家，他向我解釋為什麼我們應該知道脂肪帶有多少能量。

In order for you to live and function, you need to burn energy to, like, keep your heart beating, all your organ going and also to move around.

為了使你正常生活和身體運作，你需要燃燒能量來，像是維持心臟跳動，你的全身器官運作，和自己可以活動。

But energy doesn't come for free.

但能量不會憑空出現。

So if you are not consuming enough calories, you are going to burn that energy with your own fat.

所以要是你沒有吃進足夠的卡路里，你的身體就會用你身上的脂肪來燃燒能量。

So a lot of diet books like to teach this rule, but the problem is its wrong. Here is why.

很多減肥書籍喜歡教我們這個規則，但問題是這是錯的。原因如下：

Let's say I eat 500 calories less a day. So after 1 week it would be 3,500 calories, and I would lose a pound, right? Because I'd have to burn it.

假設我一天少吃五百卡路里，一週下來就是 3500 大卡，而我就會減少一磅，對吧？因為我需要燃燒熱量。

Yeah, and if I stayed on this diet for a year, I would burn through 52 pounds.

如果我維持這個方式一年，我將會燃燒掉 52 磅。

It'd be great! If you keep taking this thing, well, after 2 years, I'd lose 104, and after 10 years I'd lose 500 pounds, you know?

這真是太棒了！如果一直持續下去，那麼兩年後我會減掉 104 磅，而十年後我會減少 500 磅。

So obviously, at some point this rule is going to break down.

很明顯地，某一天這個規則會失效。

It will actually break down before you get to a year.

實際上，還不到一年這個規則就行不通了。

So to understand the real math behind losing weight, Dr. Chow wanted me to imagine a leaky bucket.

要了解減重背後的數學真相，趙教授要我們想像一個有漏洞的水桶。

You have some water in the bucket and that's the amount of body fat or tissue in your body.

你的水桶裡有一些水，那些是你身體脂肪或組織的總量，

And the leak represents the rate at which you are burning energy.

而那個漏洞代表你身體燃燒能量的速度。

In reality, what you are doing is adding water at the top, that's like eating food.

現實生活中你會做的是從水桶上方加水，就如同吃進食物。

And when you are in steady state, the amount of water you add at the top exactly balances the amount of water you lose at the bottom.

而當你處在穩定狀態時，你從上方添加的水量會洽好會與下方流失的水量達成平衡。

If you are pouring in more water than it is leaking, then you are going to gain weight.

如果你倒進去的水比漏掉的水還多，那麼你就會增加重量。

Now, if you think about the physics of a leaky bucket, the more water you pour into the bucket, the faster it's gonna leak.

如果你現在想想漏洞水桶的物理原理，你倒越多水進去水桶裡，水桶漏水的速度也越快

So the leak rate scales with how big you are.

所以漏水的速度與你的大小相稱。

And this is a well-known fact, that the larger you are, the more energy you burn.

這個就是大家熟知的事實，你身形越大，你燃燒的能量也越多。

You're going to burn more energy because it takes more energy just to move a larger mass.

你會燃燒更多的能量，因為單純移動一塊更大的質量就會消耗更多能量。

You have more tissue and just to keep that tissue going it takes more energy.

你有更大的身體組織了，光要使身體組織運作就會耗費更多能量。

Congratulations. You have a new steady state.

恭喜。你達到一個新的穩定狀態了。

But lets say you don't want to stay this large person that you've become.

不過我們假設你並不想維持這個龐大身形。

Well, the opposite is true, as well. You can pour in a lot less water than you are leaking. But...

嗯，反過來說也是對的。你倒進的水比漏掉的水還少。但是...

As you start to lose weight, you start to get smaller and you burn less energy and you start to metabolically adapt to your new diet.

當你體重開始減輕，你變小隻，並燃燒較少能量，然後你身體的新陳代謝會開始適應新的飲食方式。

And so you are never going to lose weight at one constant rate.

因此你永遠不會以不變的減重速度減重。

It's always going to curve from one steady state down to another. Which means...

你的體重將會從某個穩定狀態曲線型下降到另一個穩定狀態。

When you go on a diet, the 3500-calorie rule is the wrong rule.

這表示當你節食時，那個 3500 大卡的減重規則是錯的。

There is a new rule. Wait for it...

這裡有一個新的規則。等一下喔...

The new rule is, for every ten calories you eat less, you lose a pound.

新的規則就是，你每少吃 10 卡路里，你就減去一磅。

But it will take you about 3 years or more to see that the full affect of your diet, which is still pretty good.

但是這會花上你大約三年或更久的時間來看到完整的成效，這當然還是相當棒的。

All you have to do is eat a hundred calories less, you lose ten pounds.

你需要做的是少吃 100 卡路里，然後你就會減去 10 磅。

That's like a can of Coke. So you should expect the diet to be extremely slow.

100 卡路里差不多是一罐可樂。所以你可以預期這個飲食方式很慢才能看到效果。

Right, but nobody wants a slow diet.

是的，但沒人想要一個很慢見效的飲食方式。

We all want to lose 20 pounds for this summer.

我們都想在夏天前減去 20 磅啊。

What's wrong with just focusing on losing weight rapidly?

專注在快速減重到底哪裡錯了？

The problem is once you are at this new weight, they have to be vigilant for the rest of their life.

問題在於一旦你降到新的體重，身體會對接下來的存活產生警覺（所以又開始吃）。

Because losing weight is slow, gaining weight is also slow.

由於瘦得慢，所以胖得也慢。

But it slowly creeps up, and then two or three years later, bang, it hits them, and they're back up to where they were.

但體重慢慢地往上爬，兩三年後，碰！他們發現自己又回到當初的體重了。

So the mathematically approved rule for weight loss: for every 10 calories I don't eat a day, I'll eventually lose one full pound.

所以經由數學證明的減重規則：我每天少吃 10 卡路里，我最終會減掉完整的一磅。

Which means changing your steady state is a marathon and not a sprint.

這意味著改變你的穩定狀態是一場馬拉松，而非短跑衝刺。

Hey guys, this is Todd. Thanks so much for watching!

嘿大家好，我是 Todd。非常謝謝你們的收看！

If you want to have life-changing epiphanies like this one delivered automatically every single week, make sure you subscribe.

如果你想要每週自動收到改變人生、讓人產生頓悟的影片，像是現在這個，那麼請記得訂閱此頻道喔。

Also, through Facebook, Twitter, and Google Plus, we ask you, "What would you advise people who are trying to take the slow path to losing weight?"

還有，我們有在臉書、推特和 Google+ 上面問你們：「你們會提供什麼建議給那些嘗試以緩慢途徑來減重的人？」

And here's what some of you said.

這裡是你們某些人給的回應。

If you have any additional thoughts or comments, make sure you leave them in the comments section below.

如果你有其他想法或意見，記得在影片下方評論處留言。

And make sure you join us next week, we're gonna talk about the differences between white bread and sugar.

記得下週加入我們，我們將討論白麵包和糖之間的差異。

Or, are there actually any differences? We'll find out.

或者它們有什麼差別嗎？我們會知道的。

See you next week!

下週見！