BrainStuff Classics: When We Lose Weight, Where Does It Go?

When we lose weight, it doesn't just vanish. Learn how our bodies shrink fat cells in this classic episode of BrainStuff, based on this article: https://health.howstuffworks.com/wellness/diet-fitness/weight-loss/lost-weight.htm/printable

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio.

Speaker 2 (00:06):
Hey brain Stuff, Lauren vogel Bomb here with another classic
episode for you. In this one, we explore the biochemistry
of burning fat. We should note at the top here
that bodies are complicated and health is a lot more
than a number on a scale. But when we do
lose weight by burning fat, where does it go? Hey

(00:28):
brain stuff, Lauren vogl Bomb here. For many of us humans,
our body size and shape are things in flux from
one month to the next, depending on a host of factors,
both within and without our control. Our genes might be
a little tighter or a little looser. Our question of
the day is when we lose weight, where does that
lost weight go? The short answer is that our bodies

(00:50):
convert molecules in fat cells two usable forms of energy,
thus shrinking the cells. But getting this to happen isn't
just about sweating to the oldies or however you prefer.

Speaker 1 (00:59):
To work out. Understanding how our bodies perform this tummy
trimming trick requires a little more detail. We know that
weight loss hinges on burning calories. Calories are the measure
of the potential energy in the food you eat in
the form of fats, proteins, and carbohydrates. If our bodies
were cars, energy would be the gas that keeps everything running.

(01:19):
Lounging in front of the television is like cruising the strip,
while sprinting around a track is more like drag racing
at maximum speeds. In short, more work means more energy
is needed. The body uses some of the calories we
ingest to digest that very food. Once the food is
broken down into its respective parts of carbohydrates, fats, and proteins,
it either uses the remaining energy or converts to fat

(01:40):
for storage in fat cells. And as doctor who fans know,
fat cells live in adipose tissue, which basically acts like
an internal gas station storing away fuel reserves. To lose weight,
you must burn more calories or of energy than you
consume to start using up that fuel reserve. Essentially, if
you're not ingesting enough calories to fuel your additional work,

(02:01):
your body must pull from fat stores. According to the
law of conservation of mass, matter is neither created nor destroyed,
but it may alter its form through chemical reaction. Essentially,
that tells us that while we lose mass in our
bodies by burning up fat, it doesn't just disappear, it
simply changes form. When we eat, the glucose and other
sugars harnessed from carbohydrates are the first things our bodies

(02:23):
use as fuel stores. The liver stores the glucose in
the form of glycogen and releases it into the bloodstream
as necessary to keep our bodies trucking a long Think
of your blood stream as an interconnected conveyor belt that
takes necessary nutrients to the body parts that need them.
Once that glucose runs out, fat takes over. Harnessing energy
by burning fat is referred to as catosis. It works

(02:45):
like this. Hormones regulating our blood sugar levels activate an
enzyme in the blood vessels of fat tissue called liepace.
Liepace ignites fat cells to release macromolecules called triglycerides, which
are what makes fat cells fat. Sutorides are made up
of glycerool and three fatty acid chains. When they receive
the signal from lipase to exit the fat cells, the

(03:07):
triglyrides break up into their respective components and enter the
bloodstream for use. The liver snatches up the glycrool to
break it down for energy, and some of the fatty
acids move to the muscles that can farm them for
energy as well. The action of breaking down triglycerides into
usable energy is called like polysis. Once the components of
the glycerol and fatty acids are inside are muscle or

(03:27):
liver cells, organelles called mitochondria shuffle and reshuffle those compounds
to harness their potential energy, sort of like a furnace
burns wood. The mitochondria break down and recombine those components
of our fat cells and produce heat, water, carbon dioxide,
and adenysine. Triphosphate or ATP. ATP hauls potential energy in

(03:48):
its molecular bonds for use. When we exercise, like intercellular
carb loading, the water exits our bodies as sweat and urine,
and we exhale the carbon dioxide. Now that the body
has really leaved fat cells of some glycerool and fatty acids,
the cells get smaller and so sell by cell, our
body shape changes. Today's episode is based on the article

(04:15):
when we Lose weight, Where does the lost weight Go?
On How Stuffworks dot Com, written by Kristin Conger. To
hear more from Kristin, check.

Speaker 2 (04:21):
Out her podcast on Ladylife Brain Stuff is production of
I heart Radio in partnership with HowStuffWorks dot Com and
is produced by Tyler Klang.

Speaker 1 (04:28):
Four more podcasts my heart

Speaker 2 (04:30):
Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you
listen to your favorite shows.