In the wealthiest circles of Victorian England, bizarre fads ran rampant.

在維多利亞時期英國最富裕的階級當中，怪誕的風潮猖獗。

But perhaps none was as strange as the tapeworm diet, in which dieters swallowed an unhatched tapeworm and let it grow inside them by consuming undigested meals.

但或許沒有比條蟲飲食減重法更奇怪的，這種減重法讓減重者吞下未孵化的條蟲並讓牠在體內透過食用未消化餐點而成長。

Obviously, this is an exceptionally dangerous and unhealthy way to manage your weight.

這顯然是極度危險且不健康的體重管理方式。

However, while modern fad diets aren't usually this extreme, they do promise similar results⏤specifically, losing weight fast.

然而雖然現代流行的減重法通常不會這麼極端，它們都承諾類似的結果，確切地說是快速減重。

So, are there any fast diets that do work?

那麼，有確實能奏效的快速減重法嗎？

And are any of them actually healthy for you?

那之間有對你而言真正健康的嗎？

To answer these questions, let's consider a thought experiment.

為了要回答這些問題，我們看看一個思想實驗。

Sam and Felix are identical twins, both planning to go on a diet.

Sam 和 Felix 是同卵雙胞胎，兩人都打算進行飲食減重。

They share the same height, weight, fat, and muscle mass.

他們的身高、體重、脂肪量以及肌肉量都一樣。

But Sam is hoping to lose weight slowly, while Felix wants to go fast.

但 Sam 希望慢慢地減重，而 Felix 希望速成。

Sam's plan is to gradually decrease his calorie intake and increase his regular exercise.

Sam 的計畫是逐漸地將低熱量攝取並增加規律運動。

With less energy coming in and more being expended, he's creating an energy deficit inside his body.

隨著攝取的能量減少、消耗量提升，他在體內創造了能量卻乏狀態。

To compensate, Sam's body begins breaking down his emergency glucose supply stored in the liver in the form of glycogen.

為了彌補，Sam 的身體開始分解以糖原形式儲存在肝臟中的緊急葡萄糖供給量。

Then, after 4 to 6 hours, his body starts burning fat cells as a major energy source.

接著在 4 到 6 小時之後，他的身體開始燃燒脂肪細胞作為主要能量來源。

This process releases lipid droplets, which are broken down into compounds that float through the bloodstream and provide energy to organs and tissues.

這個過程會釋放脂滴，進而被分解為在血液中傳輸的化合物並提供能量給器官與組織。

Felix aims to create a similar energy deficit by dramatically cutting his calorie intake.

Felix 的目標是透過大幅削減他的熱量攝取以創造類似的能量缺乏。

Unlike Sam, who's still eating smaller meals, Felix is eating almost nothing, and his body responds by going into a starvation response.

跟餐飲減量的 Sam 不同，Felix 幾乎什麼都不吃，而他身體的反應是進入飢餓反應。

Felix's body breaks down his entire store of emergency glucose in just 18 hours.

Felix 的身體在僅僅 18 個小時內分解掉體內所有的緊急葡萄糖存量。

And while Sam steadily replenishes glycogen with every healthy meal, Felix's low-calorie diet does not.

而當 Sam 利用每一餐的健康飲食穩定補充糖原，Felix 的地熱量飲食不會這麼做。

Desperate for energy, his body starts breaking down other materials, including his muscles.

他迫切需要能量的身體開始分解其它物質，包括他的肌肉。

Meanwhile, Sam's regular exercise is maintaining his muscle mass.

同時，Sam 的規律運動維持了他的肌肉量。

This means he'll use more energy both during exercise and at rest, making it easier for him to lose weight.

這表示他無論在運動或是休息時，都會消耗更多能量，讓他減重變得更容易。

Felix, on the other hand, is losing muscle mass and burning fewer calories than ever for his body's basic functions, making weight loss even more difficult.

另一方便，Felix 的肌肉量流失，且燃燒比身體基本運作所需更少的熱量，讓減重變得更加困難。

Despite all this, there's one element of Felix's fast diet that might make him think he's on the right track.

儘管這一切，Felix 的快速減重有一個元素會讓他誤以為自己做法正確。

Every gram of glycogen is bound to several grams of water.

每一克的糖原都有數克的水。

This can add up to 2 kilograms of water weight, all of which is lost when the glycogen is depleted.

這可以累加為 2 公斤的水重，都會在糖原被消耗時流失。

For Felix, this might seem like he's losing weight fast.

對 Felix 而言，這可能看似自己正快速減重。

But as soon as he stops starving himself, his body will replenish its glycogen store and regain that weight.

但他只要一開始停止讓自己挨餓，他的身體就會重新補足糖原存量並補回體重。

Clearly, Felix's plan does more harm than good, but extreme calorie reduction diets aren't the only regimens promising to shed weight fast.

很明顯地，Felix 的計畫害多於益，但極端熱量減少的飲食法並非唯一承諾會快速減重的方法。

Plans called "detoxification diets" either promote or restrict certain foods to provide specific nutrients in high quantities.

稱為「排毒飲食法」的計畫會推廣或限制特定食物以大量提供特定養分。

These can be useful for addressing some nutritional problems, but they're far too specific to be used as general cure-alls.

這些對於解決某些養分問題有幫助，但它們太過特定，不能被當作普遍的萬靈藥。

For example, for a person with low vitamin A, a juice diet might be helpful.

舉例而言，對於缺乏維他命 A 人，果汁飲食法可能有幫助。

But for someone high in vitamin A, juicing could be disastrous.

但對體內有大量維他命 A 的人，喝果汁可能是災難性的。

And regardless of personal nutrition, maintaining a juice diet over multiple weeks is likely to compromise the immune system due to a lack of essential fats and proteins.

而不管個人營養狀態，維持數週的果汁飲食很可能會因為缺乏必要脂肪與蛋白質損害免疫系統。

Therein lies the problem with all these fast-moving diets:

因此延伸出這些快速減重法的問題所在：

Whether you're cutting calories or food groups, extreme diets are a shock to your system.

無論你是阻斷熱量或是食物群，極端飲食法對於你體內系統都有衝擊。

There are well-established rates of healthy weight loss motivated by both diet and exercise that account for genetic and medical differences.

現在有透過調節飲食與運動推動的有效且健康的減重法，可以應付基因與醫學差異。

And staying on those timelines requires a dietary lifestyle that's sustainable.

而要維持這樣的時間線需要的是可持續的飲食方式。

In fact, some of the worst side effects of extreme diets are rarely discussed since so few people stick with them.

事實上，極端減重一些最糟的副作用很少被討論，因為太少人堅持到底。

It also bears mentioning that many societies have unhealthy relationships with weight,

也值得一提的是，許多社會對於體重都有不建康的觀點，

and people are often pressured to diet for reasons other than health or happiness.

人們也常因為健康或快樂之外的原因被迫減重。

So, rather than trying to lose weight fast, we should all be taking our time to figure out what the healthiest lifestyle is for ourselves.

所以與其嘗試快速減重，我們都應該花時間想出對自己而言，最健康的生活方式。

With new diets emerging daily, all claiming to have the answer to healthy eating,

隨著每天都有新飲食法出現，全部都宣稱有健康飲食的解答，

how do we distinguish what's actually good for us from what advertisers want us to believe?

我們該如何區分哪些真正對我們有益、哪些是廣告商想讓我們相信的？

Find out how to spot a fad diet with this video.

透過這部影片學習如何辨識狂熱飲食法。