When someone loses weight where does it go?

[Orlong]

matter cant just disappear so when someone loses weight, where does it go? Down the toilet? Some people say it gets consumed as energy but even when something like wood is burned as a fuel source, it leaves behind a mass of ashes, so what happens to the weight people lose?

[Lagwin]

it's either converted to muscle or consumed as energy...the left over you shit out

[Zethras]

Energy gets stored in your body as fat.

When your brain tells your body "we need energy", it goes to the fat cells, and through a few chemical processes, turns the fat into glycogen, which other cells use for energy, which gets consumed.

The waste material then goes down the toilet.

[Sivick]

there's a big long explanation for what happens but basically when you burn your fat stores into energy the waste product comes out in various forms, the most common ones is urine and defecate. In other words, you poo it out.

[psyquest]

matter cant just disappear so when someone loses weight, where does it go? Down the toilet? Some people say it gets consumed as energy but even when something like wood is burned as a fuel source, it leaves behind a mass of ashes, so what happens to the weight people lose?

You already answered somewhat.

We burn fat (enery store) to do things. The use of this fuel provide energy for the limbs, brain etc to function. In the same way when burning wood, you have two masses left over: water that evaporates and and spent matter that is no use anymore for nrj, ashes for the wood example and for humans useless matter that is evacuated by the body through either sweat or down the toilet.

That is the laymen way to explain things.

[Ghâzh]

Basically all of those. When you start exercising, you sweat. The sweat then evaporates and moves on from your body. Your body also heats up and that heat dissipates to the air or your surroundings, you don't exactly consume the energy it just moves on. And yes, it sometimes also goes down the toilet.

[jbhasban]

Basically all of those. When you start exercising, you sweat. The sweat then evaporates and moves on from your body. Your body also heats up and that heat dissipates to the air or your surroundings, you don't exactly consume the energy it just moves on. And yes, it sometimes also goes down the toilet.

...
Sweat is only indirectly related to energy use. Sweat is used to cool you down because you are too hot. You get hot because your body is inefficient (thus why it warms up when you workout), because your body is warming up for purposes of efficiency (like when you are sick), or because the external world is hot. The evaporation has very little to do with weight loss except to the extent it temporarily lowers how much water you have in your body.

As for not consuming energy... you turn the energy into heat or kinetic energy. Since we cannot appreciate how our actions impact upon the earth (when we jump, the earth moves oh so slightly away from us, when gravity pulls us down the earth moves towards us to, when we run we rotate the world ever so slightly, when we run back home it rotates the other way), I think it is fair to say we consume it.

[Deleted]

matter cant just disappear so when someone loses weight, where does it go? Down the toilet? Some people say it gets consumed as energy but even when something like wood is burned as a fuel source, it leaves behind a mass of ashes, so what happens to the weight people lose?

It's converted to different energy sources, such as heat and energy. Think about it, how does your body stay and around 37 degrees Celsius? Heat comes from energy, energy comes from calories (kJ in physic terms), and this comes from food or in case of someone losing weight, fat and muscles that is being broken down and converted to kJ. Your body has a lot of processes going on all the time and all these requires energy that in turn generate heat or other forms of energy that leaves the body.

So in short words, the weight people lose leaves the body as some form of energy, primarily heat.

One way to see this in real life would to get some decently accurate scale, take a decently sized meal and eat it on top of the scale (so the scale weights you and the meal together). As your eating the meal, you would actually see the scale dropping as your body begins to work to digest the food (which requires energy).

[Ghâzh]

Sweat is only indirectly related to energy use. Sweat is used to cool you down because you are too hot. You get hot because your body is inefficient (thus why it warms up when you workout), because your body is warming up for purposes of efficiency (like when you are sick), or because the external world is hot. The evaporation has very little to do with weight loss except to the extent it temporarily lowers how much water you have in your body.

As a short term solution, sweating is a great way to lose weight. If you want to actually lose weight and stay that way it's obviously not gonna last. I mentioned it purely to explain different ways for the weight to "disappear". Which I thought the thread was all about, how do you actually lose that mass?

I also left out one major factor, exhaling. While you can't live without replacing the water in your body that evaporates trough sweat, you constantly exhale carbon dioxide and other gases. That is essentially how the majority of your mass would disappear in a hypothetical situation where you only consumed water and the only Excretion method was urine. You could still potentially live for a couple of weeks, keeping the amount of water in your body the same, all the time losing weight.

What it all comes down to, if you think about it, is the sum of many. In a real world scenario where you lose weight in a healthy (and long) way it's just the amount of mass that gets left out from the cycle. You gain mass by consuming food, water and the air you inhale. You then lose that mass trough various means; Excretion, sweating, exhaling and ever so slightly trough the means of energy transformation (the actual amount is so small that it can be ruled out as irrelevant). All of that waste is produced by doing work which is just another term of moving energy. If you want to lose more then you gain you either have to eat less or work more for your body to burn the amount of consumed energy reserve.

When more is coming in then going out, you lose weight. You don't even have to think or understand how energy works in that equation.

[Wiizper]

it's either converted to muscle or consumed as energy...the left over you shit out

You cant convert it to muscle.

You BUILD muscle, you dont convert anything to anything.

You body absorbs the fat.

[Magpai]

Zero-Space.

[Rotted]

You trolling oO ashs's oO

but in case your serious

It gets converted to energy, primairly your body use's carbs as a energy source to conduct a process which forms molecules called ATP, the ATP lose's the P and becomes ATD (simplified version here). This is how energy is released,

This is called a energy system, one of three, however after 90 seconds of exercise all your ATP energy is used up,

The next system is your lactic (Lactic Acid) but will skip this since you dont need it for your question,

The third system is aerobic, this is the system that will use your Fat reserve, however it takes roughly 40-45 minutes (none athlete) to "access" this is because fat is harder for the body to break down into energy than carbs, but it yields more energy so its more efficient, Fat is stored in your body around your waist (again simplified) as your fat reserve is used to "get" energy, the molecules are "burnt" thus you lose the fat, thus you lose the weight,

And just to be picky the three systems work all together at the same time, because someones bound to pick me up on that later

People say burnt, Im not sure why, probs because its easier and gives off kinetic energy (When you start to warm up from exercise and you go red, that actually your blood heating up and reaching to the surface to cool down!) but don't think of it as a fire in your body burning fat leaving behind a pile of ash's

[Deezlar]

You cant convert it to muscle.

You BUILD muscle, you dont convert anything to anything.

You body absorbs the fat.

The protein we consume does not just stack on top of our muscles... it is indeed broken down into individual amino acids, and restructured as muscle fibre to repair damaged tissue. So saying that protein is converted into muscle is equally as valid as saying it is built into muscle.

Fat is not absorbed. It is either emulsified and used as energy or stored in fat cells as a source of long term energy storage.

But back on the original point, an often overlooked way that waste material is removed from the body is through respiration.
Something that is keenly felt in those adopting a low carb diet!

in the absence of carbs, the body breaks down lipids into ketones which can be used by the brain and body as fuel in the place of blood glucose, and a side effect of this is known as "Keto Breath" where your breath takes on a weird sweet fruity smell!!

This is usually down to lower hydration in the body through ketosis promoting water loss, and ketone bodies head to the lungs to be removed from the body, rather than though urine

So in this state, you can effectively think of yourself as breathing out your fat stores (A wild simplification I know... )
Also, your wee goes borderline radioactive.. weird colour, weird smell... Also loaded with ketones!

[florestan]

a tiny part gets transferred to your surroundings as energy stored in chemical bondings is converted into heat when you are "burning" fat (mass-energy equivalence!), the rest goes down the toilet.

nota bene: mass is never "converted" into energy, it is just removed from the system ("your body") as the associated energy is removed from the system (e.g. heat via perspiration). and we are only talking about some of the mass stored in chemical bondings (which is really miniscule), not about the mass of the atoms (which you shit out).

[jbhasban]

a tiny part gets transferred to your surroundings as energy stored in chemical bondings is converted into heat when you are "burning" fat (mass-energy equivalence!), the rest goes down the toilet.

nota bene: mass is never "converted" into energy, it is just removed from the system ("your body") as the associated energy is removed from the system (e.g. heat via perspiration). and we are only talking about some of the mass stored in chemical bondings (which is really miniscule), not about the mass of the atoms (which you shit out).

Mass is converted to energy. e=mcsquared

[Ghâzh]

Mass is converted to energy. e=mcsquared

You do realize that's so extremely small amount that if all the mass you lost from your body was due to mass converting to energy we'd gain several pounds a day and become fatter and fatter? The amount is so small in reality that it can't be weighed and is really there only as a mathematical number.

[jbhasban]

You do realize that's so extremely small amount that if all the mass you lost from your body was due to mass converting to energy we'd gain several pounds a day and become fatter and fatter? The amount is so small in reality that it can't be weighed and is really there only as a mathematical number.

I do realize this. So? You said it isn't converted. It is converted. Period. If it wasnt, we wouldnt be able to move and we would all freeze to death.

[Ghâzh]

I do realize this. So? You said it isn't converted. It is converted. Period. If it wasnt, we wouldnt be able to move and we would all freeze to death.

I didn't say it wasn't converted, that was the other poster you quoted. I was just replying to you because you made it sound like all the mass converts to energy. That coupled with one of the previous posters who tried to explain that the weight you lose just basically disappears as a heat made it all sound just terribly misleading.

[Deleted]

As a short term solution, sweating is a great way to lose weight. If you want to actually lose weight and stay that way it's obviously not gonna last. I mentioned it purely to explain different ways for the weight to "disappear". Which I thought the thread was all about, how do you actually lose that mass?

I also left out one major factor, exhaling. While you can't live without replacing the water in your body that evaporates trough sweat, you constantly exhale carbon dioxide and other gases. That is essentially how the majority of your mass would disappear in a hypothetical situation where you only consumed water and the only Excretion method was urine. You could still potentially live for a couple of weeks, keeping the amount of water in your body the same, all the time losing weight.

What it all comes down to, if you think about it, is the sum of many. In a real world scenario where you lose weight in a healthy (and long) way it's just the amount of mass that gets left out from the cycle. You gain mass by consuming food, water and the air you inhale. You then lose that mass trough various means; Excretion, sweating, exhaling and ever so slightly trough the means of energy transformation (the actual amount is so small that it can be ruled out as irrelevant). All of that waste is produced by doing work which is just another term of moving energy. If you want to lose more then you gain you either have to eat less or work more for your body to burn the amount of consumed energy reserve.

When more is coming in then going out, you lose weight. You don't even have to think or understand how energy works in that equation.

Energy transformation is a major role in weight loss, far bigger than sweating. Sweating has no direct affect on body composition other than the short term effect on water levels which is restored fast again. Sweating is your body's cooling system, the only way that it somehow relates to a loss of body mass is by affecting the energy released through exercise, as sweat cools your body it allows your body to use more energy without downregulating other systems that wouldn't function properly at higher temperatures.

Excretion is mostly waste from digestion, unusable energy. This hardly affects body mass loss, as the energy from fat storages get used, not thrown out. That would be stupid to waste energy when your body needs it in a caloric deficit.

I don't see how exhaling (other than the process of converting oxygen to carbon dioxide), affects body mass composition. Again it all relates to energy, think about it just like your computer processor. Energy (from food in our case), enters the processor and has to somehow dissapate again after it has done its job, this dissapates as heat, just like on our body. Heat can't come from nothing, same goes from our body, heat comes for energy and that energy comes from all we eat. Your BMR (basal metabolic rate), is the amount of energy required for your body to operate normally. When energy is used, in any process it has to go somewhere, the usual end product is heat.

So again the simple answer is that the majority of the weight leaves your body as an energy source. That isn't to say it is the only way, but its the biggest factor.

Remember, when in a caloric deficit your body doesn't just say "Hey, Lets drop some fat". Fat molecules are being broken down and used to sustain your body's metabolic processes, so you can continue to function normally.

[Ghâzh]

So again the simple answer is that the majority of the weight leaves your body as an energy source, mostly heat. That isn't to say it is the only way, but its the biggest factor.

So you are telling me, with a straight face, that the most mass we lose while dropping weight leaves the body as heat? That's just absurd. For you to be able to transform that amount of mass purely to energy we'd have to have incredibly efficient body system to release it all. We'd be putting out huge amounts of energy by only eating and exercising.

Let's say you lose 3kg of mass. Any idea how much energy that contains?
e=mc^2, while c^2 being roughly 9 x 1016 mtr^2/sec^2, we get the following amount of energy;
3 x 9 x 1016 mtr^2/sec^2
which is around 2.7 x 1017^17 Joules

That's around half amount of energy of the first hiroshima's atomic bomb. Sounds about right to you?