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  • There are some things in life that when they're around we wish they weren't there

  • and when they're gone, we're just glad that they left.

  • For many of us, one of those things is fat.

  • But your fat tissue is full of important biological molecules called lipids -

  • long and stringy compounds of hydrogen, carbon and oxygen

  • that are great at storing energy in their chemical bonds.

  • When the molecules are broken apart they release the energy stored in their bonds.

  • We often refer to this process as "burning fat".

  • But when you "burn fat" where does that material -

  • the actual stuff that jiggles around and cushions you and insulates you -

  • where does it go?

  • Interestingly enough, a recent survey of doctors, dieticians and physical trainers

  • revealed that even the experts in fat loss didn't know the answer.

  • Although they thought they did.

  • More than 50% of the respondents thought that when you burn fat,

  • all that mass is simply converted into energy and lost as heat.

  • It's a common misconception, but it's not possible.

  • I mean just because you don't like something doesn't mean that the laws of chemistry don't apply to it

  • and one of the basic principles of chemistry is the conservation of mass.

  • This just means that the same amount of material always comes out of a reaction as goes into it.

  • Even if that reaction happens to generate heat,

  • you'll wind up with the same number of each kind of atom that you started with.

  • So, when you break up those lipids in your fat cells and release their energy

  • all of that hydrogen, carbon, and oxygen in those molecules will still be there afterward.

  • But if you burn a lot of fat, and it's not there anymore to hold your pants up or whatever,

  • where did the mass go?

  • Turns out, you exhaled it.

  • Biologists at the University of New South Wales recently did an atom by atom breakdown

  • of where the mass of your fat goes after it's burned in your body.

  • They found that for ever ten kilograms of fat that you burn, you have to inhale 29 kilograms of oygen

  • to metabolize or break down the fat and release its energy

  • and the process of breaking down that much fat produces 28 kilograms of carbon dioxide

  • and 11 kilograms of water.

  • So for every kilo of fat that you burn in your body,

  • more than 80% of that mass is lost as carbon dioxide that you breathe out.

  • The other 20% you lose as water

  • in your urine or sweat, or depending how hard you work out, your tears

  • but if you do the math, you will see that all the mass in that fat-burning reaction has been conserved.

  • 10 kilos of fat plus 29 kilos of oxygen equals 39 kilos total

  • And together they produce 28 kilos of CO2

  • plus 11 of water which also equals 39 kilos.

  • So remember that the next time you're huffing and sweating on a treadmill, or walking your dog, or

  • really doing anything that makes your body call on its energy reserves,

  • you're basically just emanating fat through your breath and your skin, but in a good way.

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There are some things in life that when they're around we wish they weren't there

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