i’m going to guess that you’ve been onthe internet before, and thus you’ve seen plenty of ads for treatments that supposedlyhelp you lose weight, “using one weird trick.†or you might have seen recent news about researchclaiming to have discovered what’s been described as “exercise in a pill.†signme up! if those things really worked, i’d be speakingfor everybody when i said, shut up and take my money! unfortunately, there’s very little scientificevidence that any drug will make you lose weight in a significant amount, safely andhealthily. however! there really are some promising treatmentsin development right now that do at least
something to help people lose weight, basedon new insights into how your body absorbs nutrients, and uses energy. so sit down, enjoy your little bacon sandwichthere, while we walk you through the facts and fictions of weight-loss in a pill. let’s start with what your doctor can dofor real, today. because: you actually can get medicationsfor weight loss, by prescription, and they come in two basic categories: appetite suppressantsand fat blockers. appetite suppressants work by blocking yourbody’s ability re-absorb the chemical signals that your brain uses, called neurotransmitters,to regulate hunger.
you’ve probably heard of a couple of theseneurotransmitters -- serotonin and norepinephrine. they’re released by your hypothalamus tomake you feel ‘full.’ so, if a chemical can block your body’sability to reabsorb those chemicals, you would feel more full, and eat less. do they work? well, sort of. and only fora while. when combined with diet and exercise, studieshave shown that prescription appetite suppressants can lead to losing around one and a half tomaybe a little over 2 kilograms of extra weight. but after six to eight weeks, the appetitecontrol center in your brain adjusts to the new levels of those neurotransmitters, andthe weight loss benefits disappear.
fat blockers work differently. they inhibitan enzyme called lipase. when you eat food that has fat in it, thosefat molecules need to be broken down into their constituent parts - glycerol and fattyacids - before they can pass through the walls of your intestines. that’s because fat moleculesare too big to pass through the membranes of your cells on their own. lipases are enzymes that break down thosefat molecules. and in order to do that, they need to bind with them. fat-blocking drugs work by bonding with lipases,which prevents them from bonding with fat. and without lipases to break it down, fatpasses through your intestines and out of
your body without ever being absorbed. so do they work? pretty well, actually. studies have shownthat they stop about 30% of the fat in your food from getting taken into your body. andover the course of two years, people who took a fat blocking drug lost, on average, abouttwo and half kilograms more than people who didn’t. but there can be some serious...and kindagross...side effects. because fat blockers keep the fat in your intestines, using thetoilet can become a messier, oilier business. so...those are your current prescription options.
then you’ve got your over-the-counter weightloss supplements. and i’m going to be honest with you here: nearly all of these are bogus.there’s very little good science that suggests that any of them will help you lose weight...atall. according to the office of dietary supplementsat the national institutes of health, the only - yes, only - one of these that has stoodup to reputable trials and is legal in the united states is green tea. green tea contains both caffeine and an organiccompound known as catechin. separately, these two things don’t contribute to any statisticallysignificant amount of weight loss, but when you put them together, they appear to actsynergistically.
caffeine stimulates the nervous system, whichhas a thermogenic effect: basically, heating up your body by getting your nervous systemto tell everything to go a little faster. and catechins inhibit the action of lipases,which gives them a minor fat blocking effect. they also stimulate the production of norepenephrine,which helps with hunger control. so together, these compounds have a mild appetitesuppressant effect that works the same way as prescription appetite suppressants. and there are apparently other mechanismsthat seem to be affected by green tea as well, but we don’t understand them all yet. so...great news, right? just start drinkinglots of green tea. i like green tea. well,
don’t go expecting a miracle. especiallyif you put a bunch of sugar in it like i do. even the most optimistic studies suggest thatdrinking green tea leads to losing a couple extra kilos over about twelve weeks. and evenso, lots of caffeine can be dangerous. so, when it comes to what’s on the markettoday, that’s it. but what about stuff that isn’t on the market? most scientists involved in making the fat-bustingdrugs of the future believe that a commercially viable option is at least ten years away.but we do know a bit about how they might work. one weight loss treatment currently in developmentaims to work by targeting your body’s circadian
rhythm. we’ve talked about this before: your circadianclock regulates rhythms in many of your body’s processes: including food intake, as wellas fat and sugar metabolism. and when your circadian clock says it’stime to burn fuel, it activates a protein in your body called rev-erb-î±. this protein works by boosting the numberof mitochondria in your cells. mitochondria are like your cells’ power plants: theytake in fuel, and turn it into energy that your body can use. and your body breaks downthe fat molecules in your fat cells to fuel your mitochondria.
so, to figure out what role rev-erb-î± couldplay in weight loss, researchers injected it into some super wimpy mice. like, i don’t know what else to call them.these mice were just...not athletic. they had poor endurance, their muscles were 60%weaker than normal mice, and their muscle cells had fewer mitochondria. they were likewhat we’d be like if we were sitting on the couch all day eating chips. the researchers injected these mice with rev-erb.and all of their cells began producing lots of mitochondria. soon, the mice could runsignificantly further and longer than untreated mice. obese mice given rev-erb lost weight,too, and their cholesterol even improved.
essentially, rev-erb provided a whole-bodyboost to their metabolism: like what happens when you get lots of regular exercise. itmade it so that the mice’s bodies just burned calories at a faster rate. even when theywere doing nothing. excellent! put that in a pill. give it tome. i want to take it. so, there’s a problem right? just tell me what the problem is. well...in low doses, rev-erb doesn’t seemto do anything. and in high doses...it’s toxic. while it speeds up the developmentof mitochondria in the short term, it impairs your cell’s ability to produce healthy mitochondriain the long term. and your cells need healthy mitochondria to...stay alive.
since rampant cell death is something we wantto avoid...a weight loss treatment based on rev-erb is going to need more work. other treatments in development seek to takeadvantage of the calorie-burning wizardry of brown fat. brown fat is good fat. yes, there’s goodfat. you actually have two different kinds of fatcells in your body: white fat cells just hang on to fat for whenever your body needs it.it’s the kind of fat that gives you the love handles and makes you jiggle. brown fat cells are different. they’re notsupposed to store fat: they’re supposed
to burn it. brown fat raises your body temperaturewhen it gets cold by breaking down fat into chemicals that release heat. it can do that because it’s packed withmitochondria. which, are brown; that’s why they’re called ‘brown fat cells.’ and the mitochondria in brown fat have a proteinin them called ucp1 that tells them to act like tiny fat-burning furnaces. so...what if there were a way to turn whitefat cells into brown fat cells? actually...there is! maybe! the key is a hormone whose existence in thehuman body was only confirmed early in 2015:
it’s called irisin. irisin turns out to be one of the many hormonesreleased by your body when you exercise, along with more well-known ones like testosteroneand adrenaline. but while testosterone stimulates muscle growthand repair, and adrenaline stimulates the breakdown of fat and sugar in your bloodstreamfor energy, irisin stimulates the production of mitochondria and ucp1 in your white fatcells. which turns them into brown fat cells. so, if scientists can figure out how to stickthat stuff into a pill or a syringe, they’d theoretically be able to kick your brown fatcell production into overdrive. which would mean lots of fat being burned without youneeding to do a thing.
but, since they’ve only just figured outthat irisin in humans exists, that’s a long way off. another potential treatment involves developinga way to inject brown fat stem cells into white fat cells, to teach the white fat cellshow to produce more mitochondria on their own. researchers at harvard have developed a compoundthat lets the brown fat stem cells do this. and i’d really love to tell you how, oreven what that compound is; but since it’s probably worth billions of dollars, it’skind of a secret. and .. we do know already know at least onedownside to this possible fat-burning drug:
the compound also happens to be an immunosuppressant.it interferes with your body’s natural inflammatory responses. which is really bad. because youneed your inflammatory response to let your immune cells reach invading bacteria and stuff.without that response, even minor infections could potentially become really serious. but other scientists elsewhere are workingon lots of other things to allow you to someday be both lazy and have a healthy weight atthe same time. still, you shouldn’t hang up your runningshoes anytime soon. for now...we’re stuck with getting and staying in shape the oldfashioned way. more running; less bacon. but thanks for watching this episode of scishow,which was brought to you by our patrons on
patreon. if you want to help support thisshow, just go to patreon.com/scishow. and don’t forget to go to youtube.com/scishowand subscribe!
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