Your body is a biological machine that follows the laws of thermodynamics and needs energy and raw materials to stay alive, which is why you eat.

你的身體是一臺生物機器，它遵循熱力學定律，需要能量和原材料來維持生命，這就是你進食的原因。

The energy from food is measured in calories, and you need a certain amount to power your internal machines.

食物中的能量是以卡路里為組織、部門計算的，人體需要一定量的卡路里來為內部機器提供能量。

Your brain thinks, your heart pumps, your gut digests, your immune system immunes, and you contract your muscles to move around.

你的大腦在思考，心臟在泵血，腸道在消化，免疫系統在免疫，而你則收縮肌肉來活動。

The harder a movement is, the more calories you burn.

動作越難，燃燒的卡路里就越多。

An hour of walking burns about 260 calories, moderate swimming 430, biking 600, running 700.

步行一小時消耗約 260 卡路里，適度游泳消耗 430 卡路里，騎自行車消耗 600 卡路里，跑步消耗 700 卡路里。

If you eat more calories than you burn, your body stores them, mostly in the form of fat.

如果攝入的熱量超過消耗的熱量，身體就會將其儲存起來，大部分以脂肪的形式存在。

One kilogram or two pounds of fat is about 7,000 calories.

一公斤或兩磅脂肪約等於 7000 卡路里。

Seems simple.

看似簡單。

To lose weight, you have to burn more than you eat, so fat is turned back into energy.

要想減肥，就必須消耗比吃進去的更多的能量，這樣脂肪才能重新轉化為能量。

There are two ways to do this.

有兩種方法可以做到這一點。

Eating less, which we'll cover in another video, and burning more, saved by moving around aimlessly, also called working out.

少吃，我們將在另一個視頻中介紹，多消耗，通過漫無目的地走動來節省，這也叫鍛鍊。

We also get told early on that exercising is healthy somehow, so working out should kill two birds with one stone.

我們很早就被告知，鍛鍊身體對健康有益，所以鍛鍊身體應該一舉兩得。

Unfortunately, this doesn't exactly work out.

不幸的是，這並不完全奏效。

It's one of these frustrating experiences where you do what you think is right, only to not see the results you deserve.

在這種令人沮喪的經歷中，你做了自己認為正確的事，卻看不到應有的結果。

In reality, focusing on exercising is not a reliable way to lose weight.

實際上，只注重運動並不是可靠的減肥方法。

Some studies show that exercise can lead to some fat loss, others that it's minimal.

一些研究表明，運動可以減少一些脂肪，而另一些研究則表明，運動的減脂效果微乎其微。

How can this be?

這怎麼可能？

It turns out that until recently, we fundamentally misunderstood what moving around a lot does to our bodies.

原來，直到最近，我們才從根本上誤解了經常走動對身體的影響。

Disclaimer.

免責聲明

The science on fat loss is complicated, and many studies compare vastly different populations, different measurements, and are complicated to understand.

有關減脂的科學研究非常複雜，許多研究比較的人群和測量方法大相徑庭，理解起來也很複雜。

And the online discussion is full of personal anecdotes.

網上的討論充滿了個人軼事。

This video covers general principles based on the current state of research.

這段視頻介紹了基於當前研究現狀的一般原則。

But when you look at the individual, there are variations.

但是，從個人角度看，情況也有不同。

It matters if you're an athlete or casually trying to lose weight.

不管你是運動員還是普通的減肥者，這都很重要。

The myth of the workout.

鍛鍊的神話

A few years ago, scientists began to compare populations in industrialized societies, which sit a lot, to hunter-gatherer communities who move around a lot.

幾年前，科學家們開始將經常坐著的工業化社會人口與經常走動的狩獵採集者群體進行比較。

The Hadza people in Tanzania walk an average of 9 kilometers a day to find wild plants and hunt animals, dig for tubers, climb trees for honey, or collect water.

坦尚尼亞的哈德扎人平均每天步行 9 公里，尋找野生植物、捕獵動物、挖掘塊莖、爬樹採蜜或取水。

They can move more in a single day than an office worker in a week.

他們一天的運動量比一個上班族一週的運動量還要大。

So, of course, they burn more calories, right?

是以，它們當然會燃燒更多的卡路里，對嗎？

But it turns out that the Hadza burn the same amount of calories per day as a typical person in an industrialized country, around 1,900 for women and around 2,600 for men, which doesn't make sense at all.

但事實證明，哈德扎人每天消耗的熱量與工業化國家的普通人相同，女性約為 1900 卡路里，男性約為 2600 卡路里，這完全不合理。

It's also not their genes, since it's the same for other hunter-gatherer tribes.

這也不是他們的基因，因為其他狩獵採集部落也是如此。

So the confused scientists looked at similar measurements in individual countries.

於是，困惑的科學家們研究了各個國家的類似測量結果。

It got even stranger.

事情變得更奇怪了。

Active people who work out regularly do burn more than inactive people, but only very little, often as low as 100 calories, the equivalent of a single apple.

經常鍛鍊的活躍人群確實比不活躍人群消耗得多，但也只是很少，通常只有 100 卡路里，相當於一個蘋果的熱量。

For some strange reason, in the long term, the amount of calories you burn is often relatively unrelated to your lifestyle.

出於某種奇怪的原因，從長遠來看，你消耗的卡路里量往往與你的生活方式相對無關。

Per kilo of muscle weight, your body has a relatively fixed calorie budget it wants to burn per day.

每公斤肌肉重量，人體每天要消耗的卡路里預算相對固定。

Sure, if you want to gain muscles by pumping iron, you also need to eat more to build and sustain them, or your new muscles wither away.

當然，如果你想通過打鐵來增加肌肉，你也需要吃更多的東西來鍛鍊和維持肌肉，否則你的新肌肉就會枯萎。

But in total, your body keeps your calorie budget per unit of you pretty stable.

但總的來說，你的身體會讓你的組織、部門熱量預算保持穩定。

And to make matters worse, if you want to lose fat, your body sabotages you in small and big ways.

更糟糕的是，如果你想減掉脂肪，你的身體會用大大小小的方式來破壞你。

First of all, when you begin to work out regularly, maybe going for a run in the morning, your body may subconsciously make you move less when you don't pay attention.

首先，當你開始有規律地鍛鍊時，也許是早上跑步，你的身體可能會下意識地讓你在不注意的時候減少運動量。

Maybe you take the elevator instead of the stairs, you sit more when you meet your friends, or you sleep longer, largely balancing out your burn again, preventing you from burning much fat.

也許你乘電梯而不走樓梯，也許你見朋友時坐得更久，或者你睡得更久，這在很大程度上又平衡了你的燃燒，使你無法燃燒很多脂肪。

You can overcome this temporarily.

您可以暫時克服這個問題。

If you do actually change your life after sitting around for years and suddenly start working out without eating more, this is a shock to your system.

如果你真的在閒置多年後改變了自己的生活，突然開始鍛鍊而不多吃東西，這對你的身體系統是一個衝擊。

You actually do burn more calories and lose fat, so you can lose weight through exercise.

實際上，你確實可以燃燒更多的卡路里，減少脂肪，所以你可以通過運動來減肥。

But this is often very short-lived.

但這往往是非常短暫的。

Your body adapts and burns fewer and fewer extra calories each week until it restores its original calorie budget.

你的身體會逐漸適應，每週燃燒的額外熱量會越來越少，直到恢復原來的熱量預算。

After a few months, you burn a very similar amount to what you did when you didn't work out.

幾個月後，你的消耗量就會與你不鍛鍊時的消耗量相差無幾。

If you stay really consistent, your burn might increase slightly and your body composition might change, but most people struggle with keeping up the habit if they don't love the extra movement.

如果你真正堅持下去，你的燃燒量可能會略有增加，你的身體成分可能會發生變化，但如果你不喜歡額外的運動，大多數人都很難堅持下去。

Which is why so many people hit a weight loss plateau.

這就是為什麼很多人都會遇到減肥高原期。

Objection.

反對。

What about muscles?

肌肉怎麼樣？

Muscles burn three times more calories at rest than fat.

肌肉在靜止狀態下燃燒的熱量是脂肪的三倍。

This sounds impressive, but tissues like your brain, skin, or intestines burn way more.

這聽起來令人印象深刻，但大腦、皮膚或腸道等組織的燃燒量要大得多。

In absolute terms, a more muscular body composition makes a difference for how many calories your body burns, but it's relatively small.

從絕對值來看，肌肉更發達的身體結構對身體燃燒的熱量有影響，但影響相對較小。

Muscles matter a lot for health, longevity, and performance, but not that much for weight loss.

肌肉對健康、長壽和工作表現非常重要，但對減肥卻不那麼重要。

Bizarre.

真奇怪

And now we're getting to the actual reason why exercise is healthy.

現在我們來談談運動有益健康的真正原因。

Why your body is sabotaging you.

為什麼你的身體在破壞你

So your body has an activity budget per day that it wants to stick to.

是以，你的身體每天都有一個活動預算，它希望堅持下去。

This setting evolved when humans had to move a lot.

這種設置是在人類需要經常移動時演變而來的。

Not because they wanted to, but because they had to find food for survival.

不是因為他們想這樣做，而是因為他們必須找到生存所需的食物。

But when food is abundant and exercise is voluntary, what does your body do with the energy that you're not using to move around?

但是，當食物充足而運動又是自願的時候，你的身體會如何處理你沒有用來活動的能量呢？

We're simplifying a lot here, and this is relatively new science, but in a nutshell, there are many different systems in your body trying to do their job as well as possible.

我們在這裡簡化了很多，這也是相對較新的科學，但簡而言之，你體內有許多不同的系統在努力盡可能地做好自己的工作。

And if there's extra energy, they seem to use it.

如果有多餘的能量，他們似乎會加以利用。

Unfortunately, this is bad.

不幸的是，這很糟糕。

When your immune cells detect injuries or infections, they trigger inflammation.

當免疫細胞檢測到損傷或感染時，就會引發發炎。

Fighter cells, alarm chemicals, and fluids flood into your tissue.

戰鬥機細胞、警報化學物質和體液湧入你的組織。

This is crucial, but it also causes damage, so it needs to be cleaned up quickly or it can become chronic.

這一點至關重要，但它也會造成損害，是以需要儘快清理，否則就會變成慢性病。

And chronic inflammation is one of the major contributors to many serious diseases, from cancer to heart failure.

而慢性發炎是導致從癌症到心力衰竭等多種嚴重疾病的主要因素之一。

If your immune system is on a tight budget, it has to be efficient with inflammation.

如果您的免疫系統預算緊張，它就必須高效地應對發炎。

With lots of free calories, though, it overcommits.

不過，有了大量的免費卡路里，它就會過度投入。

Another thing is that your glands produce hormones you don't need, like cortisol, the stress hormone which triggers your fight-or-flight response.

另外，你的腺體會分泌你不需要的荷爾蒙，比如皮質醇，它是一種壓力荷爾蒙，會引發你的 "戰鬥或逃跑 "反應。

Crucial for survival, but if you have too much of it, you get, well, very stressed all the time.

它對生存至關重要，但如果你擁有太多，你就會變得，嗯，一直非常緊張。

Chronic stress is a major cause for a bouquet of health issues, including your mental state.

長期壓力是導致一系列健康問題的主要原因，包括你的精神狀態。

For our ancestors who moved a lot and had to deal with sudden bursts of activity, fleeing from a lion, attacking that bison, this cortisol was crucial.

對於我們的祖先來說，他們經常搬家，必須應對突如其來的活動，比如逃離獅子、攻擊野牛，這種皮質醇至關重要。

But if you live a modern, sedentary lifestyle, your body is ready for action that doesn't happen, hurting itself in the process.

但是，如果你過著久坐不動的現代生活方式，你的身體就會準備好行動，但卻沒有行動，在這個過程中，你的身體會受到傷害。

Your body evolved to move regularly and is fine-tuned to a certain base level of activity.

你的身體進化到有規律地運動，並根據一定的基本活動水準進行微調。

If this activity is missing, it still uses almost the identical amount of energy just on stupid stuff.

如果缺少了這項活動，那麼僅僅在愚蠢的事情上，它仍然會消耗幾乎相同的能量。

This is why you burn a similar amount of calories whether you work out or not.

這就是為什麼無論你是否鍛鍊，消耗的熱量都差不多。

A lot of the energy you spend working out is energy you don't spend on other physical activities and body processes.

你在健身時所消耗的大量能量，是你在其他身體活動和身體過程中沒有花費的能量。

Working out is not a magic bullet, but it seems to restore an internal physical balance that seriously affects your body.

健身不是靈丹妙藥，但它似乎能恢復嚴重影響身體的內部生理平衡。

And this is also why regular exercise is so incredibly healthy.

這也是為什麼經常鍛鍊對健康如此重要。

The evidence is incredibly clear here.

這裡的證據無比清晰。

It reduces chronic inflammation and stress, it's good for your heart, may ease depression, and makes you live longer and better.

它能減少慢性發炎和壓力，對心臟有益，還能緩解抑鬱，使人更長壽、更健康。

When your ancestors evolved, they had to work hard for calories.

當你們的祖先進化時，他們必須努力工作以獲取卡路里。

Sometimes it would be easy and they could afford to chill out quite a bit.

有時會很輕鬆，他們也能放鬆不少。

But in hard times, they had to move quite a bit to feed themselves, walk longer to find prey, or dig longer to find tubers.

但在困難時期，它們不得不走很多路來養活自己，走更長的路來尋找獵物，或者挖更長的路來尋找塊莖。

If extra movement burned more calories, this would lead to a spire of starvation.

如果額外的運動會消耗更多的卡路里，這將導致飢餓的尖頂。

The less food you find, the more energy you need to find food, which doesn't even fill you up because you moved more.

你找到的食物越少，你就需要越多的精力去尋找食物，而這些食物根本無法填飽你的肚子，因為你移動了更多的地方。

It's like taking on more debt when you're in the red.

這就好比你在虧損的情況下還要承擔更多的債務。

It works for a while, but then you go bankrupt and die.

這招能管用一陣子，但隨後你就會破產和死亡。

So, for your ancestors, being able to move a lot without burning extra calories was a matter of life and death.

是以，對於你們的祖先來說，能否在不消耗額外卡路里的情況下大量運動是一個生死攸關的問題。

Okay, but this means the obesity epidemic of the modern world is not primarily caused by laziness, but by overeating.

好吧，但這意味著現代世界肥胖症流行的主要原因不是懶惰，而是暴飲暴食。

Humans evolved to be mad for calories, because of our extremely hungry brains and our extremely useless kids.

人類在進化過程中瘋狂地追求卡路里，因為我們的大腦極度飢餓，而我們的孩子又極度沒用。

Kids are cute, but unlike other species, human kids have to be fed and cared for by adults for years before they become even remotely useful.

孩子是可愛的，但與其他物種不同的是，人類的孩子必須由成年人餵養和照顧多年，才能變得稍微有用。

Because the human brain not only eats up about 20% of all our calories at rest, twice as much as our closest ape relatives, it also takes a lot of time to develop through playing, learning, and honing social skills, all the things that make us human.

因為人類的大腦不僅在休息時消耗掉我們全部熱量的 20%，是我們最親近的猿類的兩倍，而且還需要大量的時間通過玩耍、學習和磨練社交技能來發展，所有這些都使我們成為人類。

Our species is so extremely calorie expensive to maintain that we became super efficient calorie harvesters.

我們這個物種的維持需要極其昂貴的卡路里，所以我們成了超級高效的卡路里收割機。

Five hours of human hunter-gatherer foraging yields between 3,000 and 5,000 calories, while our ape relatives get no more than 1,500 in the same time.

人類在狩獵-採集過程中覓食 5 小時可獲得 3000 到 5000 卡路里的熱量，而我們的猿類親屬在同樣的時間內獲得的熱量不超過 1500 卡路里。

And we became so good at calorie harvesting precisely because of our big brains and years of social skill training.

我們之所以如此善於獲取卡路里，正是因為我們的大腦袋和多年的社交技巧訓練。

In a typical ancestral tribe, some members would spend the day searching for plants, others hunting or gathering honey, others nurturing kids.

在一個典型的祖先部落中，一些成員會花一天時間尋找植物，另一些成員會打獵或採蜜，還有一些成員會撫育孩子。

And at the end of the day, we'd share the calories so that no one would end up hungry.

最後，我們會分享卡路里，這樣大家都不會餓肚子。

Being frenetic calorie harvesters seems to be deeply part of what makes us human.

狂熱的卡路里收割者似乎是我們人類的重要組成部分。

It's not a bug, but a feature.

這不是一個錯誤，而是一個功能。

But today, it seems as if that feature has turned on us.

但如今，這一功能似乎已經背叛了我們。

We can't stop overproducing food and overeating.

我們無法停止過度生產食物和暴飲暴食。

If you want to lose fat, reducing calories is the biggest part of the answer.

如果你想減掉脂肪，減少熱量是答案的最大部分。

We'll cover diet in the next part.

我們將在下一部分介紹飲食。

So to conclude, you'll probably not lose nearly as much fat by working out as you hoped, but you will do something more important.

是以，總而言之，你可能不會像你希望的那樣通過鍛鍊減掉那麼多脂肪，但你會做一些更重要的事情。

Give your body balance and make you more resilient, and prevent or delay many of the diseases that will make your life miserable so you can enjoy a higher quality of life for much longer.

讓你的身體保持平衡，使你更有韌性，預防或延緩許多會讓你痛苦一生的疾病，讓你更長久地享受更高質量的生活。

But physical fitness is only half the equation.

但體能只是成功的一半。

To make the most of your long, healthy life, you also need a fit, active mind.

要充分利用健康長壽的生命，您還需要一個健康、活躍的頭腦。

One trained to navigate our fascinating world, and agile enough to solve any problem.

一個訓練有素的人，能夠駕馭我們這個迷人的世界，並能敏捷地解決任何問題。

Which is where our friends at Brilliant come in.

這就是我們的朋友 Brilliant 的作用所在。

Brilliant will make you a better thinker and problem solver, with thousands of hands-on, bite-sized lessons on just about anything you may be curious about.

Brilliant 將使你成為一個更好的思考者和問題解決者，它提供了成千上萬個動手實踐的小課程，內容涉及你可能好奇的任何事情。

From AI and physics to maths, data analysis and beyond.

從人工智能和物理學到數學、數據分析及其他。

On Brilliant, you'll learn through discovery by trying things yourself.

在 Brilliant，你將通過親身嘗試，在發現中學習。

And you'll not only gain knowledge of key concepts, but learn to apply them to real-world situations.

您不僅能獲得關鍵概念的知識，還能學會將它們應用到實際情況中。

All while transforming your mind into a lean, mean thinking machine.

同時將你的大腦改造成一臺精益求精的思考機器。

We've also partnered with Brilliant to create a series of lessons to take your scientific knowledge to the next level.

我們還與 Brilliant 合作製作了一系列課程，讓您的科學知識更上一層樓。

These lessons let you further explore the topics in our most popular videos.

通過這些課程，您可以進一步探索我們最受歡迎視頻中的主題。

From rabies and mammalian metabolism, to climate science and supernovae.

從狂犬病和哺乳動物的新陳代謝，到氣候科學和超新星。

I've told you my fair share of science stories over the years, and I still learned something new there.

這些年來，我給你們講過不少科學故事，但我還是學到了一些新東西。

It's like a one-on-one version of a Koska's art video.

這就像是一對一版的科斯卡藝術視頻。

And you can get started whenever, wherever, right from whatever device you'd like.

無論何時何地，您都可以通過任何設備開始使用。

Brilliant is the perfect tool for building a lifelong learning habit.

Brilliant 是培養終身學習習慣的完美工具。

One of the best ways to spend your lifetime if you ask us.

要我們說，這是度過一生的最佳方式之一。

To get hands-on with Koska's art lessons and explore everything Brilliant has to offer for free for a full 30 days, visit brilliant.org slash nutshell or click on the link in the description.

要親身體驗 Koska 的藝術課程，並在整整 30 天內免費探索 Brilliant 所提供的一切，請訪問 brilliant.org slash nutshell 或點擊描述中的鏈接。

You'll also get 20% off an annual premium subscription.

您還可以享受年度高級訂閱 8 折優惠。

Our latest journal just dropped on the shop.

我們的最新期刊剛剛上市。

Get ready to be inspired.

準備好接受啟發吧

It's our mission here at Koska's art to constantly discover new, exciting science and to present it to you in our videos.

不斷髮現新的、令人興奮的科學，並通過我們的視頻將其呈現給您，這是我們在科斯卡藝術館的使命。

That's actually hard work, but we're not alone.

這其實是一項艱苦的工作，但我們並不孤單。

We're guided by our curiosity.

我們的好奇心指引著我們。

It's what drives us to explore the world and to learn about anything and everything.

它是我們探索世界、瞭解一切的動力。

We've now created a guide to curiosity to share this skill with you.

現在，我們製作了一份好奇心指南，與您分享這項技能。

Join us across 160 thrilling interactive pages that will draw you away from your phone and into the world.

與我們一起穿越 160 個驚險刺激的互動頁面，將您從手機中吸引到世界中來。

Become aware of the countless wonders and secrets hiding in plain sight and learn skills that will change how you view the world forever.

瞭解隱藏在眾目睽睽之下的無數奇蹟和祕密，學習將永遠改變你看待世界的方式的技能。

Head to the shop now and join the curiosity movement.

現在就前往商店，加入好奇心運動。

We've also prepared some amazing deals for you.

我們還為您準備了一些令人驚喜的優惠。