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00:00Losing weight is hard, and unfortunately your body is sabotaging you every step of the way.
00:07Your body is a biological machine that follows the laws of thermodynamics and needs energy
00:12and raw materials to stay alive, which is why you eat.
00:16The energy from food is measured in calories, and you need a certain amount to power your
00:20internal machines.
00:22Your brain thinks, your heart pumps, your gut digests, your immune system immunes, and
00:28you contract your muscles to move around.
00:31The harder a movement is, the more calories you burn.
00:34An hour of walking burns about 260 calories, moderate swimming 430, biking 600, running
00:41700.
00:43If you eat more calories than you burn, your body stores them, mostly in the form of fat.
00:49One kilogram or two pounds of fat is about 7,000 calories.
00:55To lose weight, you have to burn more than you eat, so fat is turned back into energy.
01:00There are two ways to do this, eating less, which we'll cover in another video, and burning
01:05more, say by moving around aimlessly, also called working out.
01:10We also get told early on that exercising is healthy somehow, so working out should
01:14kill two birds with one stone.
01:16Unfortunately, this doesn't exactly work out.
01:20It's one of these frustrating experiences where you do what you think is right, only
01:23to not see the results you deserve.
01:26In reality, exercising is a bad way to burn fat, and until recently, we fundamentally
01:32misunderstood what moving around a lot does to our bodies.
01:37The Myth of the Workout
01:39A few years ago, scientists began to compare populations in industrialized societies, which
01:44sit a lot, to hunter-gatherer communities who move around a lot.
01:48The Hadza people in Tanzania walk an average of 9 kilometers a day to find wild plants
01:53and hunt animals, dig for tubers, climb trees for honey, or collect water.
01:59They can move more in a single day than an office worker in a week, so of course they
02:03burn more calories, right?
02:06But it turns out that the Hadza burn the same amount of calories per day as a typical person
02:10in an industrialized country, around 1,900 for women and around 2,600 for men, which
02:17doesn't make sense at all.
02:18It's also not their genes, since it's the same for other hunter-gatherer tribes.
02:23So the confused scientists looked at similar measurements in individual countries.
02:28It got even stranger.
02:30Active people who work out regularly do burn more than inactive people, but only very little,
02:35often as low as 100 calories, the equivalent of a single apple.
02:40For some strange reason, the amount of calories you burn is pretty much unrelated to your
02:44lifestyle.
02:46Per kilo of body weight, your body has a fixed calorie budget it wants to burn per day.
02:51Sure, if you want to gain muscles by pumping iron, you also need to eat more to build and
02:56sustain them, or your new muscles wither away.
02:59But in total, your body keeps your calorie budget per unit of you pretty stable.
03:05And to make matters worse, if you want to lose fat, your body sabotages you in small
03:10and big ways.
03:12First of all, when you begin to work out regularly, maybe going for a run in the morning,
03:16your body may subconsciously make you move less when you don't pay attention.
03:20Maybe you take the elevator instead of the stairs, you sit more when you meet your friends,
03:25or you sleep longer, largely balancing out your burn again, preventing you from burning
03:29much fat.
03:30You can overcome this temporarily.
03:32If you do actually change your life after sitting around for years and suddenly start
03:36working out without eating more, this is a shock to your system.
03:40You actually do burn more calories and lose fat, so you can lose a few kilos or pounds
03:45through exercise.
03:47But this is very short-lived.
03:49Your body adapts and burns fewer and fewer extra calories each day until it restores
03:54its original calorie budget.
03:56After a few months, you burn basically the same amount you did when you didn't work out.
04:01Bizarre.
04:02And now we're getting to the actual reason why exercise is healthy.
04:07Why your body is sabotaging you.
04:10So your body has a hardwired activity budget per day that it wants to stick to.
04:15This setting evolved when humans had to move a lot.
04:18Not because they wanted to, but because they had to find food for survival.
04:23But when food is abundant and exercise is voluntary, what does your body do with the
04:27energy that you're not using to move around?
04:30We're simplifying a lot here, and this is relatively new science, but in a nutshell,
04:35there are many different systems in your body trying to do their job as well as possible.
04:39And if there's extra energy, they seem to use it.
04:42Unfortunately, this is bad.
04:45When your immune cells detect injuries or infections, they trigger inflammation.
04:49Phytocells, alarm chemicals, and fluids flood into your tissue.
04:53This is crucial, but it also causes damage, so it needs to be cleaned up quickly or it
04:58can become chronic.
05:00And chronic inflammation is one of the major contributors to many serious diseases, from
05:04cancer to heart failure.
05:06If your immune system is on a tight budget, it has to be efficient with inflammation.
05:11With lots of free calories, though, it overcommits.
05:15Another thing is that your glands produce hormones you don't need, like cortisol, the
05:19stress hormone, which triggers your fight-or-flight response.
05:23Crucial for survival, but if you have too much of it, you get, well, very stressed all
05:27the time.
05:28Chronic stress is a major cause for a bouquet of health issues, including your mental state.
05:34For our ancestors who moved a lot and had to deal with sudden bursts of activity, fleeing
05:38from a lion, attacking that bison, this cortisol was crucial.
05:42But if you live a modern, sedentary lifestyle, your body is ready for action that doesn't
05:46happen, hurting itself in the process.
05:50Your body evolved to move regularly and is fine-tuned to a certain base level of activity.
05:55If this activity is missing, it still uses almost the identical amount of energy, just
06:01on stupid stuff.
06:03This is why you burn almost the same amount of calories, whether you work out or not.
06:08By working out, you're not doing anything extra, you're doing what your body is literally
06:13made to do.
06:15Working out is not a magic bullet, but it seems to restore an internal physical balance
06:19that seriously affects your body.
06:21And this is also why regular exercise is so incredibly healthy.
06:25The evidence is incredibly clear here.
06:28It reduces chronic inflammation and stress, it's good for your heart, may ease depression,
06:33and makes you live longer and better.
06:36Movement is not really made to burn your fat, though.
06:40Why humans are so hungry.
06:44When your ancestors evolved, they had to work hard for calories.
06:48Sometimes it would be easy and they could afford to chill out quite a bit.
06:51But in hard times, they had to move quite a bit to feed themselves, walk longer to find
06:55prey, or dig longer to find tubers.
06:59If extra movement burned more calories, this would lead to a spiral of starvation.
07:04The less food you find, the more energy you need to find food, which doesn't even fill
07:09you up because you moved more.
07:11It's like taking on more debt when you're in the red.
07:13It works for a while, but then you go bankrupt and die.
07:16So for your ancestors, being able to move a lot without burning extra calories was a
07:21matter of life and death.
07:23Okay, but this means the obesity epidemic of the modern world is not primarily caused
07:28by laziness, but by overeating.
07:31Humans evolved to be mad for calories, because of our extremely hungry brains and our extremely
07:37useless kids.
07:39Kids are cute, but unlike other species, human kids have to be fed and cared for by adults
07:43for years before they become even remotely useful.
07:47Because the human brain not only eats up about 20% of all our calories at rest, twice as
07:52much as our closest ape relatives, it also takes a lot of time to develop through playing,
07:57learning, and honing social skills, all the things that make us human.
08:02Our species is so extremely calorie expensive to maintain that we became super efficient
08:08calorie harvesters.
08:10Five hours of human hunter-gatherer foraging yields between 3,000 and 5,000 calories, while
08:15our ape relatives get no more than 1,500 at the same time.
08:20And we became so good at calorie harvesting precisely because of our big brains and years
08:24of social skill training.
08:26In a typical ancestral tribe, some members would spend the day searching for plants,
08:31others hunting or gathering honey, others nurturing kids.
08:34And at the end of the day, we'd share the calories so that no one would end up hungry.
08:39Being frenetic calorie harvesters seems to be deeply part of what makes us human.
08:44It's not a bug, but a feature.
08:47But today it seems as if that feature has turned on us.
08:49We can't stop overproducing food and overeating.
08:53If you want to lose fat, food is the answer.
08:55We'll cover diet in the next part.
08:58So to conclude, you'll probably not lose nearly as much fat by working out as you hoped,
09:04but you will do something more important.
09:06Give your body balance and make you more resilient, and prevent or delay many of the diseases
09:11that will make your life miserable, so you can enjoy a higher quality of life for much
09:17longer.
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