Complex Numbers

Full Of Hot Air

Today's science lesson won't mean anything to anyone these days, but when I first found it about a year ago, it was relevant.

When we lose weight, where does it go?  

Though it might one day be relevant again.

The world is obsessed with fad diets and weight loss, yet few of us know how a kilogram of fat actually vanishes off the scales.

And normally, I'd Stop Reading There. "The world" includes a whole lot of people who only wish they had an overabundance problem; not all diets are fad diets; not all weight loss is desired; not all weight loss is fat loss; and, perhaps most of all, it's not the goddamn scales that are losing weight.

But if you can make it past the stupid-ass lede, there's some decent information in there. I'd always wondered, myself, where "lost weight" actually went. I mean, there are only five means I know of to physically shed mass: pee, poo, sweat, dead skin cells, and breath. I suppose we could count "tears" as a sixth, but I've only known one person who cried enough to actually lose weight doing it, and she was absolutely no fun to be around. Or maybe it all goes into hair and disappears when we shed or cut it? Or, hey, I know, it goes into boogers that eventually get picked when hopefully no one's looking? Okay, fine, more than five. Still, which one is it? Or is it a bit of all of them?

Even the 150 doctors, dietitians and personal trainers we surveyed shared this surprising gap in their health literacy. The most common misconception by far, was that fat is converted to energy. The problem with this theory is that it violates the law of conservation of matter, which all chemical reactions obey.

That's not quite right. It's conservation of mass-energy, because mass and energy are the same entity. But only a tiny, tiny fraction of mass gets converted into energy in the body; most of it gets converted into some other substance. Also, from what I understand, "conservation" laws aren't really physical laws like gravity or action/reaction; they're observations with no known exceptions.

Some respondents thought fat turns into muscle, which is impossible, and others assumed it escapes via the colon.

It is possible to lose fat and gain muscle simultaneously, but those are entirely different processes. And I learned early on to only weigh myself after taking a great big shit.

The correct answer is that fat is converted to carbon dioxide and water. You exhale the carbon dioxide and the water mixes into your circulation until it’s lost as urine or sweat.

And we're done here. Didn't even have to slog through the entire article to find the answer. Of course, the rest elaborates on it.

If you lose 10kg of fat, precisely 8.4kg comes out through your lungs and the remaining 1.6kg turns into water. In other words, nearly all the weight we lose is exhaled.

So, basically, by losing weight we're actually contributing to greenhouse gases and climate change. Therefore, we should be celebrating fat people, not shaming them!

Every carbohydrate you digest and nearly all the fats are converted to carbon dioxide and water. The same goes for alcohol.

For the latter, lots and lots and lots of water.

The only thing in food that makes it to your colon undigested and intact is dietary fibre (think corn).

Ew! No! Gah, I can't unthink that!

So there it is. Nope, it's not diet advice. But if you've ever wondered exactly where that lost weight goes -- well, Now You Know.