Similar question
A long time ago, I was told that while we create new fat cells when we gain weight - we never lose them. Once the fat cell is there, it’ll be there forever, it will just be not as big.
Is that true? Or do the fat cells break down over time?
“One amazing fact is that fat cells do not multiply after puberty – as your body stores more fat, the number of fat cells remains the same. Each fat cell simply gets bigger!”
It wasn’t the assumption of conservation of mass that I was really objecting to. That’s reasonable. It was the idea that there is somehow significant mass lost in a nuclear reaction but not in a chemical one. There is marginally more mass lost due to binding energy conversion in a nuclear reaction but it’s still effectively immeasurable. Either way of you start out with a tonne of material and convert it to energy you end up with a tonne of material give or take a few picograms.
Thanks for all of the feedback!! So the concensus is that the vast majority of weight loss is the result of carbon dioxide being exhaled. Am I simply exhaling more volume than I am inhaling with each breath?
No, you need oxygen from the air to help make the carbon dioxide in the first place.
Nope, there’s no change in the gases being exhaled. If you weren’t losing weight you’d still be inhaling oxygen and exhaling CO2 in exactly the same amounts (broadly). The only difference is that if you are losing weight that CO2 is coming from your own body fat. If you aren’t losing weight itis coming form your last meal.
Think of it like a plane refuelling in midair. When it’s being refuelled it’s still burning the same fuel and producing exactly the same exhaust gases in exactly the same amount. However it’s not losing any weight because fuel is being added at the same rate as it’s being burned. When the refuelling stops the plane immediately begins losing weight because it’s burning fuel faster than it’s being pumped in. But the exhaust gases don’t change.
Same deal with weight loss. You don’t actually change the type of exhaust gases you produce just because you stop refuelling (eating). It’s just that the rate at which you’re adding fuel reserves as fat is slower than the arte at which you are converting them to gas.
(This being SDMB some pedant is going to come along and point out the relative efficiencies of burning glucose vs gluconeogenesis via lipid conversion and that in fact the gases do differ about. For this level of discussion it’s true enough that the gases you breathe out don’t change.)
Hold on just a second there… it’s been a while since I’ve studied this, but something smells really wrong. If you have a kilogram of reagents in a sealed container, and they undergo an exothermic chemical reaction radiating heat, you are saying mass is lost? Exactly where is it lost from? Are there fewer moles of reagents? Did we lose particles somehow? Did atoms convert to energy? Did the atomic number of the reagents change somehow, resulting in lighter moles? I sense an accounting problem here.
Think of it like a plane refuelling in midair. When it’s being refuelled it’s still burning the same fuel and producing exactly the same exhaust gases in exactly the same amount. However it’s not losing any weight because fuel is being added at the same rate as it’s being burned. When the refuelling stops the plane immediately begins losing weight because it’s burning fuel faster than it’s being pumped in. But the exhaust gases don’t change.
Brilliant analogy! I’ll definitely use this one. Thanks!