are getting some pretty good results from it. So what exactly is so different? Well,

有許多人施行生酮影食之後都有不錯的成效，那麼究竟是什麼讓生酮飲食如此有效？

most of these fad diets you find simply tells you to eat this certain type of food and avoid

大部分的減肥法通常間單的跟你說某某東西要吃某某東西不要吃

those certain type of food and voila, you're on your way to losing a hundred pounds! Of

這樣就可以減肥了

course, a lot of them don't really work and makes very little sense. What's special about

當然，大部分的減肥法通常無效而且沒有常識。

the keto diet, short for ketogenic, is that it changes how your body feels, and most importantly,

生酮飲食，將會改變你的身體機制

how your body uses energy by placing you into a state known as ketosis. And this is where

更重要的是，改變你身體消耗能量的方式，藉由一種讓身體進入叫做「酮症」的狀態

all the magic happens. In ketosis, your body starts utilizing substances

進入「酮症」之後你的身體將會開始利用

known as ketone bodies, which are produced by the breakdown of your body fat triglycerides.

一種叫「酮體」的物質，這種物質由你身體分解脂肪產生

Quick science, first understand that your body loves glucose. If it has glucose on hand,

首先你要了解身體熱愛葡萄糖，只要體內有葡萄糖

it's going to use that first for energy. Ina keto diet, the amount of carbohydrates you

身體會優先使用葡萄糖當作能量來源，在生酮飲食中，整體的碳水化合物攝取量

consume goes down, therefore, the amount of glucose goes down, too. In order to combat

將會縮限，因此，體內的葡萄糖也會下降 身體機制會對這個狀況作出反應

this, your body uses stored glucose in the form of glycogen, but then that's going to

你的身體機會開始使用儲存在肝臟的葡萄糖也就是肝醣，不過這個狀況持續下去

run out as well. The next step is to convert a substance known as oxaloacetate in the liver

肝醣也會被消耗殆盡，接下來肝臟中的草酰乙酸

into glucose. At the same time this is happening, your body is breaking down your fat into free

也會被轉化為葡萄糖，同時你的身體會開始分解自體脂肪成為脂肪酸

fatty acids and sending it to your liver to metabolize another important substance known

並進入你的肝臟並代謝另一個重要的物質 「乙醯輔酶A」

as acetyl CoA. Acetyl CoA is then placed into the Krebs cycle in the liver cells to produce

「乙醯輔酶A」將會參與肝臟細胞的「三羧酸循環」來產生能量

energy. But it can't do that right now. Remember that oxaloacetate that was being broken down

不過，肝臟還不會這樣進行，還記得「草酰乙酸」分解成為葡糖糖嗎？「草酰乙酸」

into glucose? Well, oxaloacetate is also needed for the Krebs cycle to function. Now your

「草酰乙酸」也是「三羧酸循環」所必須的一環

liver has all of these acetyl CoA lying around so it decides to break it down into two substances

肝臟中的這些「「乙醯輔酶A」」可以被分解成兩種叫做

called acetoacetate and beta-hydroxybutyrate, which are known as ketone bodies. It sends

「乙酰乙酸」和 「β-羥基丁酸酯」也就是所謂的「酮體」

them into the bloodstream where other body cells pick them up, convert the ketone bodies

接下來這兩樣物質會藉由血液輸送到身體的細胞

back into acetyl-CoA, into Krebs cycle, and energy is produced! This is also really good

並轉換回「乙醯輔酶A」並進入「三羧酸循環」並產生能量！

news for your brain, since even though your brain loves glucose, too, it can function

對你的大腦來說也是非常好的，因爲即使大腦喜歡用葡萄糖當能源，但它也可以利用「酮體」當作燃料

on ketone bodies as well. In fact, ketone bodies provide more energy per gram for the

事實上，「酮體」能提供比「葡萄糖」更多的單位能量

brain versus glucose, so win-win for your mental capacity!

所以對你的大腦來說這是一個雙贏的局面

Now so far, everything sounds good. Your body no longer relies heavily on carbohydrates,

目前為止，一切聽起來都不錯。你的身體不再倚賴碳水化合物

it burns a lot of fat, and your brain functions pretty well. But of course, there's always

並燃燒大量的脂肪，而且你的大腦能夠運作的更好

a catch, a number of catches in this case. Studies show that power output decreases in

不過事情總有一體兩面

cases where maximum intensity is required. This makes sense because the breakdown of

研究指出高強度的運動下表現會略有下降。這是由於

glucose via glycolysis, plays a crucial role in providing immediate energy for your body.

運動所需的立即能量主要由分解葡萄糖產生

With no glucose and glycogen in your body, intense workouts become a lot harder. And

當你沒有葡萄糖的時候，高強度的運動將會更辛苦

the lack of glycogen also affects muscle growth, since there is a strong positive connection

而且由於缺少葡萄糖也會對於肌肉增生有一定的影響

between glycogen availability and protein synthesis. Take the glycogen away, and the

當你沒有葡萄糖的時候

process slows down. Oh, and there's the keto flu, something that

肌肉的生長將會被影響。噢還有就是 「keto flu」

happens when your body starts transitioning off of carbs and rely more heavily on ketone

「keto flu」發生在你的身體開始轉變由使用碳水轉為使用酮體的時候

bodies. The "keto flu," which isn't an actual flu, contains symptoms such as headaches,

「keto flu」不是真的流感，不過他的症狀例如 頭痛

fatigue, coughing, nausea, and even upset stomach. The positive note, though, is that

疲勞、咳嗽、噁心、甚至消化不良

it passes quite quickly and won't come back again unless you come out of ketosis.

不過這些症狀應該很快就會過去，而且不會再發生，除非你脫離「酮症」

The keto diet is also very food restrictive. A conventional diet has you eating roughly

生酮飲食是一種非常嚴格的飲食控制 傳統的減肥

20% fat, 30% protein, and 60% carbs. The keto diet, on the other hand, shifts you all the

你大概會吃 20% 脂肪，30% 蛋白質和 60% 的碳水化合物

way to 70% fat, 25% protein, and 5% carbs, or below 30 grams. That's a huge change that

生酮飲食你必須吃 70% 脂肪，25% 蛋白質和 5% 的碳水化合物（或低於30公克），這是非常大的差別

some people just cannot do. Cutting out so many carbs is easier said than done. This

而且並不是每個人都能辦到，改吃如此少的碳水化合物並不是一件容易的事情

is a huge battle itself, and a lot of times, a losing battle.

這件事情並不容易辦到，甚至失敗率也蠻高的

But even with the drawbacks, people still advocate for it. And the reason that's the

不過即使有這些缺點，生酮飲食被認為是有用的

case can be summed up from this study in 2004 from the Annals of Internal Medicine: "a low-carbohydrate

一份從2004的研究指出低碳的減肥法（像是生酮）

diet (such as a keto diet), had better participant retention" compared to a low-fat diet. That

相較於低脂的減肥法，有更好的效果

is saying, even with all the drawbacks, individuals on a keto diet find it much easier to stick

也就是說生酮飲食即使有缺點，不過它比傳統的節食法更容易持續下去

to the diet more so than a conventional diet. This is because, with so much more fat and

因為提高的油脂含量與高質量蛋白質

protein-dense foods, your satiety, or fullness level, goes up much faster. A 200 calorie

你的飽足感會上升

chicken breast or 200 calories worth of green leafy vegetables, will make you feel more

兩百大卡的雞胸肉或兩百大卡的綠色蔬菜

full than say a 200 calorie, carb-heavy pasta. But even if this is the case, a calorie is

會比你吃兩百大卡義大利麵（高碳）來的有飽足感

still a calorie. Yes, protein and fat calories will make you feel more full, but it won't

不過卡路里依然重要，當然蛋白質與脂肪會讓你容易感覺飽

help you lose weight if you're still eating more calories than you burn.

如果你吃下的卡路里大於你消耗的，你還是無法減肥

So is the keto diet worth it? Well, it all comes down to, "It depends." If you're someone

所以生酮飲食值得嘗試嗎？恩，看情況

that struggles a lot with feeling full whenever you go on a weight loss diet, then yes, the

如果你實行節食法但飽足感讓你一直失敗。

keto diet might help you battle those feeding frenzies. Just remember those drawbacks that

生酮也許可以幫助你戰勝食慾。不過要記得一些副作用

will occur, and at the end of the day, it still comes down to calories in versus calories

可能會發生，不過最終也會過去，最後終還是要回到總卡路里的計算

out. What's your take on the keto diet? Shared

你對生酮飲食的想法是什麼呢？ 在留言分享你的想法

your comments below! Thanks for watching and please subscribe for more future health and

感謝你的收看，並請訂閱更多的健康與運動影片。

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