Weight Loss Pills: Fact Or Fiction?

I’m going to guess that you’ve been on
the internet before, and thus you’ve seen plenty of ads for treatments that supposedly
help you lose weight, “using one weird trick.” Or you might have seen recent news about research
claiming to have discovered what’s been described as “exercise in a pill.” Sign
me up! If those things really worked, I’d be speaking
for everybody when I said, SHUT UP AND TAKE MY MONEY! Unfortunately, there’s very little scientific
evidence that any drug will make you lose weight in a significant amount, safely and
healthily. However! There really are some promising treatments
in development right now that do at least SOMETHING to help people lose weight, based
on new insights into how your body absorbs nutrients, and uses energy. So sit down, enjoy your little bacon sandwich
there, while we walk you through the facts and fictions of weight-loss in a pill. Let’s start with what your doctor can do
for real, today. Because: You actually can get medications
for weight loss, by prescription, and they come in two basic categories: appetite suppressants
and fat blockers. Appetite suppressants work by blocking your
body’s ability re-absorb the chemical signals that your brain uses, called neurotransmitters,
to regulate hunger. You’ve probably heard of a couple of these
neurotransmitters — serotonin and norepinephrine. They’re released by your hypothalamus to
make you feel ‘full.’ So, if a chemical can block your body’s
ability to reabsorb those chemicals, you would feel more full, and eat less. Do they work? Well, sort of. And only for
a while. When combined with diet and exercise, studies
have shown that prescription appetite suppressants can lead to losing around one and a half to
maybe a little over 2 kilograms of extra weight. But after six to eight weeks, the appetite
control center in your brain adjusts to the new levels of those neurotransmitters, and
the weight loss benefits disappear. Fat blockers work differently. They inhibit
an enzyme called lipase. When you eat food that has fat in it, those
fat molecules need to be broken down into their constituent parts – glycerol and fatty
acids – before they can pass through the walls of your intestines. That’s because fat molecules
are too big to pass through the membranes of your cells on their own. Lipases are enzymes that break down those
fat 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, fat
passes through your intestines and out of your body without ever being absorbed. So do they work? Pretty well, actually. Studies have shown
that they stop about 30% of the fat in your food from getting taken into your body. And
over the course of two years, people who took a fat blocking drug lost, on average, about
two and half kilograms more than people who didn’t. But there can be some serious…and kinda
gross…side effects. Because fat blockers keep the fat in your intestines, using the
toilet can become a messier, oilier business. So…those are your current prescription options. Then you’ve got your over-the-counter weight
loss 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…at
all. According to the Office of Dietary Supplements
at the National Institutes of Health, the only – yes, ONLY – one of these that has stood
up to reputable trials AND is legal in the United States is green tea. Green tea contains both caffeine and an organic
compound known as catechin. Separately, these two things don’t contribute to any statistically
significant amount of weight loss, but when you put them together, they appear to act
synergistically. Caffeine stimulates the nervous system, which
has a thermogenic effect: basically, heating up your body by getting your nervous system
to 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 appetite
suppressant effect that works the same way as prescription appetite suppressants. And there are apparently other mechanisms
that seem to be affected by green tea as well, but we don’t understand them all yet. So…great news, right? Just start drinking
lots of green tea. I like green tea. Well, don’t go expecting a miracle. Especially
if you put a bunch of sugar in it like I do. Even the most optimistic studies suggest that
drinking green tea leads to losing a couple extra kilos over about twelve weeks. And even
so, lots of caffeine can be dangerous. So, when it comes to what’s on the market
today, that’s it. But what about stuff that ISN’T on the market? Most scientists involved in making the fat-busting
drugs 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 development
aims to work by targeting your body’s circadian rhythm. We’ve talked about this before: Your circadian
clock regulates rhythms in many of your body’s processes: including food intake, as well
as fat and sugar metabolism. And when your circadian clock says it’s
time to burn fuel, it activates a protein in your body called REV-ERB-α. This protein works by boosting the number
of mitochondria in your cells. Mitochondria are like your cells’ power plants: they
take in fuel, and turn it into energy that your body can use. And your body breaks down
the fat molecules in your fat cells to fuel your mitochondria. So, to figure out what role REV-ERB-α could
play 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 like
what 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 run
significantly 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-body
boost to their metabolism: like what happens when you get lots of regular exercise. It
made it so that the mice’s bodies just burned calories at a faster rate. Even when they
were doing nothing. Excellent! Put that in a pill. Give it to
me. 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 seem
to do anything. And in high doses…it’s toxic. While it speeds up the development
of mitochondria in the short term, it impairs your cell’s ability to produce healthy mitochondria
in the long term. And your cells need healthy mitochondria to…stay alive. Since rampant cell death is something we want
to avoid…a weight loss treatment based on REV-ERB is going to need more work. Other treatments in development seek to take
advantage of the calorie-burning wizardry of brown fat. Brown fat is good fat. Yes, there’s good
fat. You actually have two different kinds of fat
cells 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 not
supposed to STORE fat: they’re supposed to BURN it. Brown fat raises your body temperature
when it gets cold by breaking down fat into chemicals that release heat. It can do that because it’s packed with
mitochondria. Which, are brown; that’s why they’re called ‘brown fat cells.’ And the mitochondria in brown fat have a protein
in them called UCP1 that tells them to act like tiny fat-burning furnaces. So…what if there were a way to turn white
fat cells into brown fat cells? Actually…there is! Maybe! The key is a hormone whose existence in the
human body was only confirmed early in 2015: It’s called irisin. Irisin turns out to be one of the many hormones
released by your body when you exercise, along with more well-known ones like testosterone
and adrenaline. But while testosterone stimulates muscle growth
and repair, and adrenaline stimulates the breakdown of fat and sugar in your bloodstream
for energy, irisin stimulates the production of mitochondria and UCP1 in your white fat
cells. Which turns them into brown fat cells. So, if scientists can figure out how to stick
that stuff into a pill or a syringe, they’d theoretically be able to kick your brown fat
cell production into overdrive. Which would mean lots of fat being burned without you
needing to do a thing. But, since they’ve only just figured out
that irisin in humans exists, that’s a long way off. Another potential treatment involves developing
a way to inject brown fat stem cells into white fat cells, to teach the white fat cells
how to produce more mitochondria on their own. Researchers at Harvard have developed a compound
that lets the brown fat stem cells do this. And I’d really love to tell you how, or
even what that compound is; but since it’s probably worth billions of dollars, it’s
kind of a secret. And .. we do know already know at least one
downside 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 you
need 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 working
on lots of other things to allow you to someday be both lazy and have a healthy weight at
the same time. Still, you shouldn’t hang up your running
shoes anytime soon. For now…we’re stuck with getting and staying in shape the old
fashioned 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 this
show, just go to patreon.com/scishow. And don’t forget to go to youtube.com/scishow
and subscribe!


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