# Thread: When someone loses weight where does it go?

1. Originally Posted by Ghâzh
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?
Sorry, but your seperating one variable out of lots, our body doesn't act like in a vacuum. Besides your calculations are wrong, what exactly are you trying to show me? If you want to calculate the energy of 3kg of fat it's much more simple, 1 gram of fat is 9 calories. 9 x 3000 = 27000 calories (111000kJ)

Just a few reasons your calculations are soooo wrong:
Firstly, that equation has no connection to energy stored in fat
You assume all energy is being released at once

Other than the equation not making sense in regards to what we're discussing, your also calculating the wrong the factor. Fine you got some energy number, but what would you use that to? We're discussing heat, which is a form of energy. What you need to find out is how much energy it requires to sustain our body temperature, this includes outside variables such as wind speed and outside temperature.

The fact of the matter is, any metabolic process in our body produces some kind of end product. Mostly one sort of energy is being converted to another. If we're in a caloric surplus, our body stores energy in fat cells, this energy is then released when we're in a caloric deficit, it is being released to serve a purpose and the fact is that whatever this purpose might be the end product generates some kind of heat.

Of course, it's not a one-sided story, some ends being exhaled (in oxygen to carbon dioxide process), some gets urinated (through fat cells being used in the liver and metabolic processes), but these are a small part of a major system constantly in the works. Even when we exhale, urinate, excrete the process to make us able to do these things produce some kind of heat, all that work adds up to much more heat than the energy used in each seperate variable.

Another edit: Assume your calculations were true, imagine how much a person would have to eat to gain 3kg in a week or two. With that thought, its absurd to assume what your saying has any truth.

Just on a side note to people saying you shit out fat. That is so wrong. Your body burns fat cause it's needed, not just to get rid of it. That would be like throwing out leftover food supplies when people are starving on a cruise. You feed it, don't throw it out.

2. Originally Posted by Lagwin
it's either converted to muscle or consumed as energy...the left over you shit out
You can't convert fat into muscle.

Muscle is built by the muscle being torn slightly and then rebuilding stronger.

3. Originally Posted by Labze
Sorry, but your seperating one variable out of lots, our body doesn't act like in a vacuum. Besides your calculations are wrong, what exactly are you trying to show me? If you want to calculate the energy of 3kg of fat it's much more simple, 1 gram of fat is 9 calories. 9 x 3000 = 27000 calories (111000kJ)

Just a few reasons your calculations are soooo wrong:
Firstly, that equation has no connection to energy stored in fat
You assume all energy is being released at once

Other than the equation not making sense in regards to what we're discussing, your also calculating the wrong the factor. Fine you got some energy number, but what would you use that to? We're discussing heat, which is a form of energy. What you need to find out is how much energy it requires to sustain our body temperature, this includes outside variables such as wind speed and outside temperature.

The fact of the matter is, any metabolic process in our body produces some kind of end product. Mostly one sort of energy is being converted to another. If we're in a caloric surplus, our body stores energy in fat cells, this energy is then released when we're in a caloric deficit, it is being released to serve a purpose and the fact is that whatever this purpose might be the end product generates some kind of heat.

Of course, it's not a one-sided story, some ends being exhaled (in oxygen to carbon dioxide process), some gets urinated (through fat cells being used in the liver and metabolic processes), but these are a small part of a major system constantly in the works. Even when we exhale, urinate, excrete the process to make us able to do these things produce some kind of heat, all that work adds up to much more heat than the energy used in each seperate variable.

Another edit: Assume your calculations were true, imagine how much a person would have to eat to gain 3kg in a week or two. With that thought, its absurd to assume what your saying has any truth.

Just on a side note to people saying you shit out fat. That is so wrong. Your body burns fat cause it's needed, not just to get rid of it. That would be like throwing out leftover food supplies when people are starving on a cruise. You feed it, don't throw it out.
No.

You are wrong.

Your body uses fat as energy, yes. But it has waste products. One of them is lactic acid. Lactic acid is excreted from the body. Another is acetone which is a ketone and which is excreted. There are a lot of different byproducts the body cannot utilize when fat is utilized as energy. So while you may only get 9 calories of energy from 1 gram of fat, that is because that 1 gram of fat is not being turned completely into energy. It is because very little of that fat is being used as energy. If your body was able to turn all of its mass into energy, you would never be able to get skinny. Think about how much energy is in one single atom and you really think 1 gram of fat which is TONS of atoms only has 9 calories in it? You are a fool if you think so.

---------- Post added 2013-04-07 at 06:14 PM ----------

Originally Posted by Zildjian
You can't convert fat into muscle.

Muscle is built by the muscle being torn slightly and then rebuilding stronger.
Eh, we actually do not know how muscles grow in terms of them being torn or not. That is a hypothesis at this stage.

4. Originally Posted by jbhasban
No.

You are wrong.

Your body uses fat as energy, yes. But it has waste products. One of them is lactic acid. Lactic acid is excreted from the body. Another is acetone which is a ketone and which is excreted. There are a lot of different byproducts the body cannot utilize when fat is utilized as energy. So while you may only get 9 calories of energy from 1 gram of fat, that is because that 1 gram of fat is not being turned completely into energy. It is because very little of that fat is being used as energy. If your body was able to turn all of its mass into energy, you would never be able to get skinny. Think about how much energy is in one single atom and you really think 1 gram of fat which is TONS of atoms only has 9 calories in it? You are a fool if you think so.
I'm really not following. If i came across as saying that we don't excrete ANY mass at all, that wasn't what i ment. But these waste products are miniscule amounts, we're talking grams of of lost kilos.

So your saying that not all energy contained in fat is used, care to ellaborate?

If the body were able to use all our mass as energy, why wouldn't we be able to get skinny? I think that sounds exactly like why we are able to do so. Why else would we get skinny, if our mass isn't used as means to energy?

Originally Posted by jbhasban
Think about how much energy is in one single atom and you really think 1 gram of fat which is TONS of atoms only has 9 calories in it? You are a fool if you think so.
What? I have never.. Unless i seriously misunderstand what your saying, your making some seriously weird claims.

5. Originally Posted by Labze
I'm really not following. If i came across as saying that we don't excrete ANY mass at all, that wasn't what i ment. But these waste products are miniscule amounts, we're talking grams of of lost kilos.

So your saying that not all energy contained in fat is used, care to ellaborate?

If the body were able to use all our mass as energy, why wouldn't we be able to get skinny? I think that sounds exactly like why we are able to do so. Why else would we get skinny, if our mass isn't used as means to energy?

What? I have never.. Unless i seriously misunderstand what your saying, your making some seriously weird claims.
E=mc^2 speaks to the conversion of mass to energy. It means you can take a piece of fat and turn it into electricity with the fat simply disappearing. The energy would be all that is left. The mass would be completely and utterly gone. You take a closed environment, you take some fat, you convert the mass to energy, and the environment is left extraordinary hot. The amount of energy in mass is obscenely large. For instance, one gram of hydrogen would be able to power a 100 watt light bulb for 4 billion hours.

Our body utilizes fat by taking advantage of the covalent bonds in it. It takes the energy from those bonds and applies them. No atoms are never destroyed as a result. The amount of mass that is utilized can barely be measured at all. The vast majority of the mass we have in our bodies is excreted as unusable waste product. Our bodies are not some sort of sun capable of nuclear fission.

6. Originally Posted by jbhasban
E=mc^2 speaks to the conversion of mass to energy. It means you can take a piece of fat and turn it into electricity with the fat simply disappearing. The energy would be all that is left. The mass would be completely and utterly gone. You take a closed environment, you take some fat, you convert the mass to energy, and the environment is left extraordinary hot. The amount of energy in mass is obscenely large. For instance, one gram of hydrogen would be able to power a 100 watt light bulb for 4 billion hours.
And exactly how is that relevant?

Seriously, stop taking something so much out of proportion, the OP asks a question and you begin to talk about physics that has absolutely zero relevance in regards to his question.

7. Originally Posted by Labze
And exactly how is that relevant?

Seriously, stop taking something so much out of proportion, the OP asks a question and you begin to talk about physics that has absolutely zero relevance in regards to his question.
It has everything to do with it. Hes asking where fat goes to. I am showing it cannot go strictly into energy. Which means it must be excreted as something.

8. Originally Posted by jbhasban
It has everything to do with it. Hes asking where fat goes to. I am showing it cannot go strictly into energy. Which means it must be excreted as something.
What happens to the energy that enters your computer, lightbulb, oven? It dissapates as heat. Same happens with our bodies. What else would keep our body temperature elevated above our surroundings? Fat is a container of energy, as is everything else we eat. Of course it can be used as such.

**Edit

Okay i begin to understand what you're actually getting at, my bad. However, the fat stored in our fat cells are at its most usable state. When we eat fats and other nutrients lots of it gets excreted, but the stored fat won't be excreted as the more 'unusable' parts are digested and have left the body.

9. Originally Posted by Labze
What happens to the energy that enters your computer, lightbulb, oven? It dissapates as heat. Same happens with our bodies. What else would keep our body temperature elevated above our surroundings? Fat is a container of energy, as is everything else we eat. Of course it can be used as such.

**Edit

Okay i begin to understand what you're actually getting at, my bad. However, the fat stored in our fat cells are at its most usable state. When we eat fats and other nutrients lots of it gets excreted, but the stored fat won't be excreted as the more 'unusable' parts are digested and have left the body.
You are getting closer but you are still not there. The fat in our body is a high store of energy. Yes. But we cannot utilize everything in it. We can only utilize a small amount of it. We cannot utilize the protons and neutrons in the matter in order to fuel our bodies as our bodies are not capable of nuclear fission. What we can utilize is the energy found in the electrical bonds in the atomic structure of fat. We use that energy to turn ADP to ATP. That ATP is then turned back into ADP and the loose phosphate is used to power our bodies. There are other energy pathways that our body uses with fat. However, in the end, we will be left with excess protons, neutrons, and electrons that cannot be used in the atomic structure that they fall into (they are low energy structures). Our body gets rid of those. We then consume more high energy structures in order to suck the energy from them to turn the structures already in our body into high energy structures so we can power our body. These are very complex organic chemical pathways that require a graduate degree to fully understand. What isn't hard to understand is that our body cannot do nuclear fission. So that means the atoms that are found in our fat cells must be excreted from our body when we lose weight. Some of it will be excreted in our breath, some in our sweat, some in our urine, some in our excrement, some in our tears, etc.

The electricity that enters our computers is not mass. It is already energy. So it can be utilized completely without any conversion. The heat your computer gives off is a result of the machine not being 100% efficient. If a machine were 100% efficient, it would not give off any heat. Think of a refrigerator. Fridges, when left open, end up heating your house because the fridge is not completely efficient. How light and heat relate is more complex but in general light can excite atoms that it reaches. The excited state can be thought of as heat. When the excited state falls down to the lower state, the energy reaches out to atoms near it and excites those atoms to a higher state. So heat can transfer from one atom to another. Very simplistic explanation.

When I said you would never be able to get skinny, it is because I would not be surprised if we would be able to power our entire life with a few lbs of fat if we were completely efficient and capable of turning the fat completely into energy.

10. Fat is a source of energy. Thats like saying when you put gas in your car where does it go?

11. Originally Posted by Lilly32
Fat is a source of energy. Thats like saying when you put gas in your car where does it go?
Gas is structured CH₃(CH₂)...CH₃ + impurities. The impurities are excreted as gasses or liquids out the exhaust or stay in your car. The gas is combined with oxygen and heat. The hydrocarbons in gas join with the oxygen to form C02, C0, and H20. You may also get some peroxide or other structures from time to time. All of that goes out the exhaust.

12. Wow. Almost two whole pages and I've yet to see the two major byproducts of respiration.

Water and carbon dioxide.

That's where the weight goes.

13. Originally Posted by jbhasban
You are getting closer but you are still not there. The fat in our body is a high store of energy. Yes. But we cannot utilize everything in it. We can only utilize a small amount of it. We cannot utilize the protons and neutrons in the matter in order to fuel our bodies as our bodies are not capable of nuclear fission. What we can utilize is the energy found in the electrical bonds in the atomic structure of fat. We use that energy to turn ADP to ATP. That ATP is then turned back into ADP and the loose phosphate is used to power our bodies. There are other energy pathways that our body uses with fat. However, in the end, we will be left with excess protons, neutrons, and electrons that cannot be used in the atomic structure that they fall into (they are low energy structures). Our body gets rid of those. We then consume more high energy structures in order to suck the energy from them to turn the structures already in our body into high energy structures so we can power our body. These are very complex organic chemical pathways that require a graduate degree to fully understand. What isn't hard to understand is that our body cannot do nuclear fission. So that means the atoms that are found in our fat cells must be excreted from our body when we lose weight.
Sorry, but you are still overcomplicating something so simple. First of all i have done my 3 years bachelor in food and nutriotional science, and soon starting my candidate so I'm fully capable of understand where you are going. During digestion our body removes most, if not all of the lesser nutritional bits from food that gets excreted. That means when we store fat in fat cells, this is energy ready to be used at any given time without further digestion, as soon as signalled the fat gets extracted as triglycerides which then enters the blood stream as an available source of energy via lipolysis. There isn't much of a waste product during this stage, of course any process leaves some sort of waste that gets excreted but this is still miniscule in the whole weight loss business.

Seriously, if you want to you can do the experiment yourself. Starve for a few days, see some kilos dropping off and meassure your excretion. You won't end up with a bucket filled with 1,5kg of poo even though you ended up losing 3-4kgs of weight, your pee will not account for a large amount either when the water is taken out of the weight.

14. Originally Posted by Jarion
Wow. Almost two whole pages and I've yet to see the two major byproducts of respiration.

Water and carbon dioxide.

That's where the weight goes.
I thought I covered those when I said our body excretes it. I suppose I should state that excretion refers to any way in which our body gets rid of atoms.

---------- Post added 2013-04-07 at 08:43 PM ----------

Originally Posted by Labze
Sorry, but you are still overcomplicating something so simple. First of all i have done my 3 years bachelor in food and nutriotional science, and soon starting my candidate so I'm fully capable of understand where you are going. During digestion our body removes most, if not all of the lesser nutritional bits from food that gets excreted. That means when we store fat in fat cells, this is energy ready to be used at any given time without further digestion, as soon as signalled the fat gets extracted as triglycerides which then enters the blood stream as an available source of energy via lipolysis. There isn't much of a waste product during this stage, of course any process leaves some sort of waste that gets excreted but this is still miniscule in the whole weight loss business.

Seriously, if you want to you can do the experiment yourself. Starve for a few days, see some kilos dropping off and meassure your excretion. You won't end up with a bucket filled with 1,5kg of poo even though you ended up losing 3-4kgs of weight, your pee will not account for a large amount either when the water is taken out of the weight.
I don't know how I would go about measuring the air I breathe out, the sweat I give off, the water from my tear ducts, etc. The gas we give off is considerable. Honestly, talk to your professor. Ask him if our body is capable of nuclear fission. If it isn't, how do you possibly suggest our body can utilize the atoms in our fat cells as energy? It is extremely hard to turn matter into energy.

Here, read this, it gives a better explanation than I have here: http://www.medbio.info/Horn/Body%20E...ody_energy.htm

15. Originally Posted by 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?
You see, the fact of the matter is that you dont actually burn fat, carbohydrates og protein, when your body uses these components to create energy your body simply breaks it up to fuel the process of turning ADP into ATP which every cell will then use to to fuel other processes. After being used to fuel a process the ATP will be turned into ADP again. So when you use excess bodyfat to create ATP out of ADP, all of the material which is stripped of energy will then come out as faeces and urine.

16. sigh. jbhasban. Just stop. We're all VERY impressed.

OP if you're truly interested in where our stored energy (fat) goes when we lose weight, investigate cellular respiration. http://en.wikipedia.org/wiki/Cellular_respiration

But the short answer is the water and carbon dioxide we exhale. Not our urine, or feces.

Here's the summary equation for the reaction that happens as a very long multistep process in our cells.

C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + heat
ΔG = -2880 kJ per mole of C6H12O6

17. To put it simply, it depends what kind of mass they are losing. There are various metabolic pathways to store sugars, lipids (fats), proteins, etc. and then convert them to usable forms when needed. Most of these pathways end up converting one thing to another, yield a few high energy molecules (ATP, for example, has high energy phosphate bonds) and then we expel the remainder as waste. The waste is the leftover, which varies with pathway, but is almost always CO2 and some small hydrocarbons that aren't useful for further generation of high energy molecules.

As everyone has said before, to put a really complicated answer into simple terms, you use what you can and the rest is waste. Some of the waste is gaseous CO2 and liquid H2O that we breathe/pee out, but there is also some waste that is excreted if it is not recycled/recyclable by the body.

18. ATP (energy production) doesnt involve fat in any way, shape, or form, at all...ever.
Its Glucose + Oxygen to yield CO2+H20 and ATP. Fat is a lipid while glucose is a carb. Lipids are stored energy and are only burned off after you exhaust all of your Sugar (Carbs)

19. Originally Posted by Lilly32
ATP (energy production) doesnt involve fat in any way, shape, or form, at all...ever.
Its Glucose + Oxygen to yield CO2+H20 and ATP. Fat is a lipid while glucose is a carb. Lipids are stored energy and are only burned off after you exhaust all of your Sugar (Carbs)
You are confusing people with your ignorance on this topic. ATP is the only source of energy that the human body has. The process of creating ATP needs energy from substances that contain energy. In this case, these substances are fats, carbohydrates and protein.
The point that you are missing is that the body creates glycogen, which is a carbohydrate out of lipids (fat).

20. Originally Posted by Lilly32
ATP (energy production) doesnt involve fat in any way, shape, or form, at all...ever.
Its Glucose + Oxygen to yield CO2+H20 and ATP. Fat is a lipid while glucose is a carb. Lipids are stored energy and are only burned off after you exhaust all of your Sugar (Carbs)
>.>

http://en.wikipedia.org/wiki/Fatty_a..._and_oxidation

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•