When is a pound lost and where does it go?

well you can stay at maintainance at burn 500 cals a day n you will lose a pound every week.
2nd ques when you are burning fat look for when thing when you go to toilet to pee you will notice something white in your pee is like chicken fat thats how some of your fat comes out n some as a sweat. because when i did a diet few years back when the white thing came in pee i got scared that its something serious but found out its nothing just fat so a doctor knows best.

well you can stay at maintainance at burn 500 cals a day n you will lose a pound every week.
2nd ques when you are burning fat look for when thing when you go to toilet to pee you will notice something white in your pee is like chicken fat thats how some of your fat comes out n some as a sweat. because when i did a diet few years back when the white thing came in pee i got scared that its something serious but found out its nothing just fat so a doctor knows best.

Really? All this time I thought that white stuff was phlegm that came from moist cupcakes. Who knew that it was really chicken fat?

If you boil it, it can make a wonderful chicken soup.

If you boil it, it can make a wonderful chicken soup.

If you boil it, it can make a wonderful chicken soup.

It's more of an Egg Drop Soup.

If you boil it, it can make a wonderful chicken soup.

It's more of an Egg Drop Soup.

Mmmm that's my favorite soup. But wait. What happens to the fat I eat from this soup?

It comes back out, once you burn it. Some in your pee again, some as sweat.
[/quote

Now that's what I call recycling! Endless supply of egg drop soup!]

I have two questions that have been bugging me. So I hear you lose a pound of fat for every 3500 calories. This being the case, when does that pound actually drop off? Theoretically, if I were to eat my maintenance calories and burn 3500 calories through exercise would I lose a pound the moment I reached that calorie burn or does it take a day or two to remove itself?


This second part of the question sounds ridiculous, I'll admit, but where exactly does that pound of fat go? I get that it's converted into energy but I have a hard time getting my head around the idea that something that occupies a certain space (the pound of fat) can essentially disappear into something which no longer occupies space.


The second problem is something that confuses me when it comes up in any context. I just can't quite understand how something can become nothing. Any thoughts welcome.

When you burn fat, you break it down into ketones that you can use as energy. Those ketones are used pretty fast and they eventually will be turned into CO2 that you breath off or pee out has HCO3. That's how a pound of fat disappears

The original poster asked some interesting questions, and I like the way she thinks.

A "heat engine" takes in heat and converts a portion of it into mechanical work. When nutrient molecules in the body are combined with oxygen ("burned"), that's an exothermic reaction; it produces heat. Muscle cells use that heat energy to do work. The whole human body can be usefully regarded as a heat engine.

And yes, calories *are* energy, rigorously and exactly. A calorie is the amount of heat energy required to increase the temperature of a gram of water by a Celsius degree. (A nutritional calorie -- the sort we all talk about here -- is 1000 calories, as defined. It is also equal to 4186 joules, which is the work done by one newton of force over a parallel displacement of 4186 meters. A "typical" person weighs about 667 newtons, and can be lifted a little over six meters, straight up, by a nutritional calorie of mechanical work.)

A pound is lost when a pound of stored nutrients in the body (hopefully, fat) has been converted to ... well, not just energy. If an entire pound of fat were all converted to energy (according to E = mc^2), a dieter would be like an atomic bomb. But, as another commenter pointed out, chemical bonds in the pound of fat are broken, some of it is oxidized, heat is produced by that reaction; most of the rest of the broken-down nutrient molecules become waste and are eliminated in the same way as any food waste. The energy required by your body is supplied by the food you eat; if you don't eat "enough," you're in a calorie-deficit situation, and some stored body fat is internally "eaten" as well. As the OP said, about 3500 cal of deficit is equivalent to a pound of fat; as for WHEN this happens: as soon as your body requires a single calorie more than you've eaten, 1/3500 of a pound gets burned. When your cumulative deficit reaches 3500 cal, a full pound will have been used. (For the elimination of the unburned waste, I suppose there's a time delay measured in hours.)

But, in any case, that pound of fat didn't turn into nothing. A very small fraction of it is turned into heat and used by your muscles; the vast majority is turned into feces and urine, and returns to nature in the usual ways.

People ask me from time to time how much weight I've lost. Of course, I tell them that "lost" is probably too strong a term. I pretty much know where all of it is. Most of it's at the grocery store; quite a bit is at Burger King and Taco Bell and so on. I could go pick it up at any time. So, it's not really lost; it's more like "misplaced." I hope to leave it that way.

ok... now that i have picked myself back up off of the floor... **wipes away tears**

the question about burning calories IS a good one. and without getting too scientific (i'm a writer, Jim, not a science officer) i can break it down this way:

when you start a fire in your fire pit, barbeque or fireplace, you stack in fuel. this fuel can be logs or charcoal. then you light the fire. the logs and charcoal burn - technically calories, funny but true - and break down into gases, smoke, ash and i'm sure a lot of other things that i was asleep in chem when they explained. the energy is used to make the fire burn, and anything that is NOT that energy, is broken down to waste.

your body isn't that different. but it's your metabolic rate rather than a lighter that gets the fire going. you actually ARE expending heat energy - this is why your core temp goes up and you sweat and all the other stuff that happens when you're hot. Your body uses the stored energy by burning it. anything that is not needed to keep the fire going, is converted into waste - sweat, exhaled breath, poop and yeah, even some urine.

i hope that worked for you.

These are fantastic responses, thank you!