Shadowing Practice: The Science of Fat - Learn English Speaking with Video
Creating lesson...
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Fat.
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Blubber.
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Pudge.
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It goes by many names, but its true identity can only be learned by consulting with the All-High Council of Nerds.
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They call it adipose tissue.
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Adipose tissue is everywhere.
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It's in your bones, your muscles, your organs, and there's tons and tons of it under your skin.
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And if you accidentally inhale the contents of your entire refrigerator, it grows.
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Like, how does your body convert whatever you happen to throw in your stomach into yellow jelly under your skin?
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And how on earth does going to hot Pilates every Wednesday get rid of it?
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To find out, we're gonna take a field trip inside this guy's Big Mac.
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Big Macs and food in general have two parts.
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Big macronutrients and little micronutrients.
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Micronutrients don't contain any energy.
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They're just little guys.
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Macronutrients, on the other hand, contain all the energy in your food.
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And they only come in a few flavors.
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Proteins, carbs, fats, and alcohol.
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Alcohol is a bit special, so we're gonna ignore it.
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It also doesn't come with the Big Mac, which is currently in our subject's mouth.
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The mouth is gonna break that Big Mac into a bunch of smaller Macs
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and add some saliva to make it a nice Mac slurry.
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Also, some of the carbs are gonna get jumped.
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These guys are called enzymes.
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Their entire job is to punch macronutrients until they break into smaller pieces.
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And in the mouth, they have it out for the carbs.
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After that, the trio slides down the esophagus and into the stomach.
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There we are welcomed by the stomach juices and some of their enzyme pals.
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Also, everybody's getting jumped.. by the enzymes.
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After a couple hours of your stomach blending your food, it reaches a nice pulp of mac slush marinated in stomach acid.
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The food then slowly passes through to the small intestines where they receive another warm welcome by some fresh pancreas juice.
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In fact, they're getting so welcomed that they decide to leave.
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Yeah, that's allowed apparently.
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They just have to use the door in the intestinal cells.
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But they're too big.
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Hold on, light bulb, let's keep getting clobbered until we're small enough to pass through.
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This was a terrible idea, but they did it anyway because that's how digestion works.
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Look man, I don't make the rules.
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Eventually, the proteins get beat into amino acids, the carbs get shoved into sugars, and and the fats get mangled into smaller fats.
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Finally, they can all fit through the door and make their escape.
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There are two paths outside the intestinal cell.
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A blood vessel with a tiny mousel entrance and a lymphatic vessel which is shut with the gates of Gartholomew.
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The carbs, which are now sugars, and proteins, which are now amino acids, slip right into your blood which is a straight shot to the liver.
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But the intestinal cells turn the fats into big bundles called chylomicrons, which are way too fat to go through blood vessels,
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and instead must go through the gates of Gartholomew.
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Here it goes through a series of vessels of all shapes
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and sizes and takes a nice tour of your body until finally, just under your left collarbone, they get spit out into the bloodstream.
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Now you have a big ball of fat floating around in your blood.
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Great!
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But if they just stay like that, you'd die pretty quick.
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So your body has two teams to deal with these little piggies.
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Each team is made up of enzymes and molecules that take some fat and break it down into bite-sized pieces.
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One team takes those pieces and feeds it to your muscles for energy, while the other team feeds those pieces to your fat cells.
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And the one directing it all is a hormone called insulin.
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Right after you eat a meal, your pancreas dumps a truckload of insulin into the bloodstream.
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Insulin's job is essentially to make sure the teams in your adipose tissue are working overtime, and the teams in your muscle tissue have their lazy boys on full throttle.
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That is, they're relaxing extremely hard, taking a very intense and serious break.
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This results in the majority of that incoming fat being cut up and fed to your fat cells as energy for later.
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When a fat cell gets one of these pieces, it reassembles it into a bigger piece of fat for storage.
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Then, it gives this big piece as an offering to the glorious sphere of fat.
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And this, ladies and gentlemen, is why both this guy and this guy have about the same amount of fat cells.
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Because rather than creating new fat cells, the same fat cells just keep getting stuff fuller and fuller and fuller.
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Of course, even the pros have a limit.
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The maximum size a fat cell can expand is about 1 700th the size of a banana.
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Which might seem small, but a healthy fat cell is usually 1 2 thousandths of a banana.
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Once a cell reaches that limit, it sends SOS signals to dormant fat cells and a new fat cell is born.
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But this is rare, which may come as a surprise to my fellow Americans.
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And so most of the time, a cell is simply pumped fuller and fuller with fat, which is energy saved for later.
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So if later does come, hypothetically speaking, how does this blubbery energy stuff get used up?
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It all starts with hormones.
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When you're hungry, your pancreas releases hormones.
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When you're exercising, your adrenal glands release hormones.
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When you're sleeping, your brain releases hormones.
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And some of those hormones go to your fat cells.
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But what do they do once they get there?
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What's a measly hormone going to do to extract all that energy juice?
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Nothing really, they kind of just float around.
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And so, oh, it seems the hormone has fallen into a devious trap.
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How unfortunate.
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This happens because of receptors on the outer layer of your fat cells
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that are basically on watch for these hormones at all times.
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When they catch one, they trigger a chemical reaction that wakes up two killer enzymes inside the cell.
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These absolute machines start systematically butchering the fatty molecules into smaller and smaller molecules,
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only for them to then be shredded up by another enzyme into little baby fatty acids.
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At this point, the pieces of fat are so small
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that they just slip right through the cell walls and leak into the outside world.
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This is bad because the outside world is mostly water, and fats do not like water.
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Oh look, a convenient clump of protein is floating around.
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Oh look, the fat is now on the convenient clump of protein.
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Oh look, they're entering the the bloodstream.
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Neat!
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They float around for a bit until they pass a tissue like this one, which is burning a lot of fat.
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In this case, it's the heart pumping blood.
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But it could have also been muscles working or the liver doing liver stuff.
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These tissues have vacuums, which easily sucks fat right off the clump of protein and into the cell.
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There, it is greeted by another friendly protein and escorted to the mitochondria.
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The powerhouse of the The cell, unspeakable horrors, happen inside that mitochondria.
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But afterwards, our fatty friend pops out of some ATP.
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And then, it explodes!
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This reaction gives energy to the cell, and therefore, the tissue as a whole.
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Wow, those muscles must be working so hard to explode so much fat.
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You're probably thinking.
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And you'd be wrong.
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In fact, this guy is sleeping like a baby right now.
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The more physically demanding an activity is, the less it relies on fats for energy, and the more it relies on sugars, which comes from carbs.
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You do still use more fat during exercise than you do during rest, because of the sheer amount of energy you're using,
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but during rest your body is much more reliant on fat.
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This has quite a lot of implications when it comes to losing weight.
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But before we get to that, there is one thing about adipose tissue which I have yet to reveal.
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A secret so secretive that even the high council of nerds didn't know about it until the mid-90s.
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This layer of blubber under your skin has a direct line of communication with your brain.
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And it does that by using...
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hormones.
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Again.
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Each fat cell is constantly releasing a hormone called leptin.
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Chunky fat cells release a lot of leptin, while small fat cells release less leptin.
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Leptin tricks through your blood, all around your body until it reaches the blood vessels in your brain, where it sneaks through and finds your hypothalamus.
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The hypothalamus was expecting this and keeps track of how many of these guys show up.
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This is because your hypothalamus is smart.
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It knows that if there's a lot of leptin, then the fat cells are already fat and it makes you want to eat less food.
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If there isn't much leptin, then it knows that reserves are low and it makes you want to eat more food.
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Basically, your fat is constantly self-reporting directly to the brain exactly how fat it is at any given moment,
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and the hypothalamus adjusts how hungry you feel accordingly.
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And it does this to keep you at a healthy baseline.
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But if that's the case, then how does something like this happen?
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When your adipose tissue gets this big, it produces insane amounts of leptin,
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which should make you have essentially no desire to eat anything at all.
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And it would if your hypothalamus was just a bit smarter.
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See, your hypothalamus doesn't actually know how much leptin is healthy, it only knows how much leptin is normal.
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So if you're overweight for a long enough time, a high amount of leptin becomes normal.
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And therefore, your hypothalamus will make you feel hungry like normal.
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This makes it very, very, very hard to lose weight.
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Imagine you start a diet, hypothetically speaking, and your body starts tapping into more of your fat reserves.
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The fat cells start shrinking and therefore make less leptin.
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Your hypothalamus sees less leptin than normal and makes you hungrier.
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But you persevere.
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You trek on.
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You lose seven pounds in a week.
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Then your hypothalamus notices another huge drop in leptin and signals an emergency.
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Basically, your brain sets off alarms that you're starving.
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And because it thinks you're starving, it slows down metabolism to use energy more efficiently, which makes weight loss slower.
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When you're losing weight, your body fights against you to stay overweight.
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So why is your body so against becoming healthier?
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For most of human history, the average person was constantly threatened by one thing, starving.
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In the caveman days, losing weight meant you didn't have enough food to eat, which meant you were dying.
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Losing weight was almost never a good thing.
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That is, not until we got Big Macs, Doritos, and Walmart.
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We simply aren't built for this.
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So losing weight is impossible, right?
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Yeah, pretty much.
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That's what I would say if I was wrong.
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The hypothalamus can adjust its baseline.
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It's just a little shy.
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Which is why the key to losing weight is doing it slowly.
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Very slowly.
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I'm talking half a pound a week slow.
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One pound a week is also safe, and you can lose up to two pounds a week if you're speedrunning.
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But if you try and go faster than that, you're probably in for a bad time.
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At this slower rate, your hypothalamus still increases appetite, but it's much more manageable.
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giving it time to slowly change the baseline and figure out a new normal.
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But slowly do what, exactly?
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Should you diet?
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Exercise?
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Pray to the sun god?
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Well all three won't hurt, but none of them really get to the crux of the issue.
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Hormones.
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Fat will only shrink if there is some hormonal signal to shrink.
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And this hormonal signal only comes when you don't have enough energy.
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Which is why to lose weight, you have to be in an energy deficit.
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That means making your body use a bit more energy than the energy you eat.
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To explain what I mean by eating energy, I must mention the forbidden word which I have yet to utter this entire video.
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Calories.
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Calories measure energy, not food.
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For example, one ton of TNT will release about a million calories.
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When we talk about calories with food, we're measuring how much energy your mitochondria can explode from one of our macronutrient friends.
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So when I say eat less calories, I do not mean eat less food.
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I'm talking about energy, the macronutrients in the food,
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which means you can eat less calories whilst actually eating more food.
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But even then, it's not as simple as put out calories and don't put them in.
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Being in an energy deficit does not always mean you're being healthy, it just means you're losing weight.
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If you don't ever move from your bed and only eat spinach and kale, you're in an energy deficit and will lose weight.
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It's also very unhealthy.
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If you live exclusively off pizza but run up mountains and wrestle alligators to burn those calories off,
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you're in an energy deficit and will lose weight.
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And still very unhealthy.
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Being in a calorie deficit will work for weight loss, no matter how you do it.
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But you should not prioritize your weight over your health.
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Anyways, you really gotta stop coming through this drive-thru, man.
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I see you like twice a day.
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But that's gonna cost you approximately one subscribe, and tips are highly encouraged and accepted in the form of likes and comments.
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Vocabulary and speaking notes for this lesson
This B2 speaking lesson is built on the video “The Science of Fat”. The speaker keeps coming back to these words: fat, cell, energy, weight, leptin. This video has 190 sentences and 2309 words to shadow. The speech runs for 12:54. The speaker talks at a natural 179 words per minute, close to everyday conversation. Only 80% of the words are among the 3,000 most common in English, so the vocabulary is demanding.
Key vocabulary in this video
The 15 most advanced words in the video, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| leptin noun | /ˈlɛptɪn/ | A protein hormone produced in adipose tissue; it plays a role in regulating appetite and metabolism. |
| hormone noun | /ˈhoɹmoʊn/ | Any substance produced by one tissue and conveyed by the bloodstream to another to effect physiological activity. |
| hypothalamus noun | A region of the forebrain located below the thalamus, forming the basal portion of the diencephalon, and functioning to regulate body temperature, some… | |
| calorie noun | /ˈkæləɹi/ | A non-SI unit of energy, equivalent to 4.184 kilojoules, that can raise the temperature of a kilogram of water by one degree Celsius. This is the unit normally… |
| carb noun | /kɑɹb/ | The hole on a pipe which is covered and opened to control the inflow of air. |
| enzyme noun | /ˈɛn.zaɪm/ | A biomolecule that catalyses a biological chemical reaction: either a globular protein with this function or an RNA molecule with this function. |
| adipose adjective | /ˈæd.ɪ.poʊs/ | Containing, composed of, or consisting of fat; fatty. |
| macronutrient noun | Any of the elements required in large amounts by all living things. | |
| deficit noun | /ˈdɛfəsɪt/ | Deficiency in amount or quality; a falling short; lack. |
| float verb | /fləʊt/ | To be supported by a fluid of greater density (than the object). |
| bloodstream noun | /ˈblʌd.stɹɪim/ | The flow of blood through the circulatory system of an animal |
| clump noun | /klʌmp/ | A cluster or lump; an unshaped piece or mass. |
| intestinal adjective | /ɪnˈtɛs.tɪ.nəl/ | Relating to the intestines. |
| mitochondrion noun | /ˌmaɪtəˈkɑndɹiən/ | A spherical or ovoid organelle found in the cytoplasm of eukaryotic cells and containing genetic material separate from that of the host; it is responsible for… |
| pancreas noun | /ˈpæŋ.kɹi.əs/ | A gland near the stomach which secretes a fluid into the duodenum to assist with food digestion. |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| go through verb | To travel from one end of something to the other. |
| come through verb | To come into a room or other space through a door or passageway. |
| cut up verb | To cut upward. |
| figure out verb | To come to understand; to discover or find a solution; to deduce. |
| find out verb | To discover, as by asking or investigating. |
| pass through verb | To go through, to travel through, to transit or lie across a place or from one place to another. |
| put out verb | To blind (eyes). |
| set off verb | To leave; to set out; to begin a journey or trip. |
Sentences worth repeating
Short, complete lines from the video that you can reuse in everyday conversation:
- Look man, I don't make the rules.
- When you're hungry, your pancreas releases hormones.
- When you're exercising, your adrenal glands release hormones.
- When you're sleeping, your brain releases hormones.
- Basically, your brain sets off alarms that you're starving.
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | be learned · are called · are welcomed |
| Relative clauses who / which + clause — extra information about a person or thing | Mac, which is · vessel which is · carbs, which are |
Pronunciation to watch
The speaker uses 46 contractions and reduced forms, such as you're, don't, gonna. Say them the short way, as you hear them.
- The “th” sounds: unhealthy /ʌnˈhɛl.θi/, threaten /ˈθɹɛt.n̩/
- The “sh” and “zh” sounds: implication /ˌɪmpləˈkeɪʃən/, sheer /ʃɪɚ/
- Long words — get the stress right: intestinal /ɪnˈtɛs.tɪ.nəl/, mitochondrion /ˌmaɪtəˈkɑndɹiən/, alligator /ˈæl.ɪ.ɡeɪ.tɚ/, manageable /ˈmænəd͡ʒəb(ə)l/, oesophagus /ɪˈsɑfəɡəs/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like leptin, hormone, hypothalamus.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.