ELI5: How does metabolism actually work?

I'm not an expert - I just read about this the other day - so this is how I can summarize what I remember:

Well, you can think of metabolism as two brothers having a self-sufficient company. One brother Catab(r)o the other and Ana(bro) Lism. They are the perfect bros

Catabro is the one who takes care of breaking down walls. The walls are large molecules - like proteins. He takes them and and breaks them down into smaller units that are way easier to handle by his brother -

Anabro , well he's the dude. He takes these perfectly sized blocks and starts building where he is needed. Bones, Muscles, you name he'll build it.

How can you make these brothers work faster? What's their Metab(r)olic rate?

They accept payments of hormones. Most hormones you can think of actually. Some you can pay through eating, some through activity. That's a super complex network.

But I think you are asking why things work differently for you and your roomie.

The brothers working for you .. well think of them always having the same body as the person who hires them to build. For them to even get to a place of productivity you need a certain contract

The contract reads something like : We the Metabros, in order to work at a set speed, require you : consisting of _ (enter weight) of fat + _ enter weight of lean muscle to consume at least _ this many calories to build up your body. In order to build we also require that you provide : cortisol, adrenaline, glucagol (and here is a lot of fine print consisting of more hormones etc.)

And that's where the differences are, your roommate's could have anything specified in that fine print. And it's very hard to read.

Research says that about 60% comes from mass of body minus fat. Then fat at about 7 % And 3% experimental error

The 30 missing percent remain - unexplained (!)

That fine print must be fucking fine

Well have I told you that they have an agent that only has a landline you can call , but he kind of never hears it because he is fucking busy - he's called Hypothalamus. He just does his thing for all the other working parts of your body including the metabros. I have no idea how you can call him ask about the fine print and tell him to regulate body temperature, hunger, rage, thirst. But he does all that.

He is so busy.

/r/explainlikeimfive Thread