Maintaining a healthy weight is a goal for many people,

and aerobic exercise is one way to kick your metabolism into high gear,

to help burn excess fat by using the chemical energy that's stored inside it.

The fat in your body is actually a connective tissue made up of cells called adipocytes, or fat cells.

Which raises the question: What happens to these cells when you burn up your fat stores?

Do the cells just disappear when their energy is released?

Well, here's the skinny on your fat cells…

They never really go away.

But they can grow and shrink, depending on whether you're gaining or losing weight.

And that's a good thing.

You don't want your fat cells to completely go away

because that tissue plays an important role in your anatomy.

Fat gives your body structure, cushions your organs,

and keeps you insulated to help regulate your body temperature.

But the primary function of fat cells is to store energy.

When you eat, sugars in your food are the first form of energy to be used.

But when you're not eating, your body needs a way to access energy from somewhere so you can still function.

So fat is actually super important.

Like any other cell in your body, your fat cells have a nucleus and organelles.

But they're specialized, so that 90% of each cell is basically just a pouch for fat storage.

And the fat-storage unit that your body uses is called a triglyceride.

It's made up of three fatty acid chains and a molecule of glycerol,

a kind of alcohol that serves as a backbone for the fatty acids to attach to.

The bonds in fatty acids contain a lot of chemical energy, so it's in this form that fat sits around in your adipocytes.

When they're needed for energy, triglycerides are broken up into its component fatty acids, with the help of a protein known as LPL.

Those fatty acids can then pass through the membrane of the fat cell,

where they're dispatched to be metabolized elsewhere so their energy can be unleashed.

In the process, the fat cell shrinks.

But if more triglycerides get stored than get used up, that's what causes adipocytes to grow.

And larger fat cells means more adipose tissue.

Losing weight requires expending enough energy to break down the triglyceride stores into fatty acids that can further be used as energy, shrinking the fat cells.

But as anyone who has tried to lose weight knows, it takes a lot of work.

And even if you do lose weight, it's easy to gain back, since it requires less energy to store excess fat than to burn it.

So, without using up any of that stored energy, fat cells will continue to sit, unused and forgotten.

Thanks for asking, and thanks especially to all of our patrons on Patreon who keep these answers coming.

If you'd like to submit questions to be answered, or get some videos a few days early,

go to patreon.com/scishow.

And don't forget to go to youtube.com/scishow and subscribe!

♪ OUTRO ♪