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No Really, Where Does Fat Go When You Lose It?

where does fat go

Have you ever wondered where fat goes once you lose it?

You may have had your theories over time, or you perhaps you couldn't care less "who cares! It's gone, right? Woo hoo!" However, if you're curious about the magic of fat loss and exactly where those pounds disappear to I'd love to have this way cool and nerdy discussion with you.

First, mass cannot be created nor destroyed; this is the core principle of the law of conservation of mass. What the principle means is that things don't just "poof" appear and "poof" disappear. The fat you lose must go SOMEWHERE.

Second, a common misconception is that fat is converted into muscle and muscle converted into fat. In reality, it's physiologically impossible because fat and muscle are made of two completely different types of tissue with different types of cells. Fat is always fat, and muscle is always muscle.

So far I've dispelled two incorrect notions, but I haven't offered up the answer. You're probably thinking, "GET ON WITH IT!" When you burn fat, where does it go?? Here's a hint, your lungs are a VERY crucial component of your weight loss goals.

A few years ago an Australian man named Ruben Meerman lost about 30lbs, and he was perplexed about where the fat went. Ruben might have been the perfect person to ask this question because Ruben was also a physicist. To answer his question, he teamed up with Andrew Brown, a Lipid Researcher at the University of New South Wales, and together they set out to find out just where the fat on our bodies go. Here is what the pair discovered:

When fat metabolizes or "burns," you end up with water, energy, and carbon dioxide. 84 percent of the fat you burn ends up as carbon dioxide and 16 percent as water in the form of sweat, tears, urine, and other bodily fluids. So what does that mean? The vast majority of the fat you burn actually gets breathed into the air. Yep, your lungs that are responsible for ridding your body of excess body fat.

On the other hand, what the duo also found was that an alarming amount of personal trainers, doctors, and dietitians don't know what happens to fat once it is metabolized. Many of them didn't know at all; some thought that we peed & pooped it out (which isn't entirely wrong), and surprisingly, some seriously thought it became muscle. Yikes!

So mystery solved right? Now you can BREATHE easy!

If you're feeling particularly inquisitive, I've included Meerman's and Brown's research below.

[ British Medical Journal Published Study ]