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When somebody loses weight, where does the fat go?

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Re: When somebody loses weight, where does the fat go?

#41

Post by Cd00d »

k__ wrote: post #27
krallja wrote: post #3

Reminds me of the question “what are trees made of?” (The answer to both questions is “mostly atmospheric CO2.”)

Hehe, true. I once saw a documentary about "big animals" in the past. Like, why did we have giant spiders and insects while they have a rather simple respiratory system that doesn't scale very well. Because: trees! Somehow plants managed to create wood, which bound the C from CO2, but the rest of the biosphere didn't know what to make of the wood. So there were more and more trees and more and more C got removed from…

I thought ants were what made short work of the wood. Something about formic acid? Do you know more - I need to reset my ignorance.

Re: When somebody loses weight, where does the fat go?

#42

Post by DoodleBuggy »

ZeWaren wrote: post #30

It's pretty obvious when you do long fasts. Every time I fast for more than I week, I lose several kilos doing nothing, not going to the bathroom even once except to pee.

What is your intake during the fast? Bone broth? Water? Electrolytes?

Re: When somebody loses weight, where does the fat go?

#43

Post by yetihehe »

Filligree wrote: post #26
k__ wrote: post #15

Earlier quoted context omitted.

200g are what would be "breathed out" in one hour without exercise? So you can only increase your "burn rate" by 20%?

A remarkable fraction of your energy consumption is spent on basic maintenance, and of the rest, far more than you'd think is spent on the brain. Your body is extremely efficient, by engineering standards, but that includes locomotion. Exercise is still a good way to drop in weight, but not simply due to burning up the fat; that could happen anyway. What seems to be happening is that the exercise improves the body's…

> Very few have the willpower to literally starve themselves.

Yep, tried this recently with closed loop weight control. After about 8-10kg (from 116kg) lost it's almost impossible to keep on going, you can't control yourself enough to not eat.

Re: When somebody loses weight, where does the fat go?

#44

Post by kgabis »

ransom1538 wrote: post #39
mikeash wrote: post #4

For anyone coming straight to the comments looking for an answer to the question: it turns into CO2 (and a bit of water) and you breathe it out. When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.

"For anyone coming straight to the comments looking for an answer to the question: it turns into CO2 (and a bit of water) and you breathe it out." That is why you weigh less when you wake up in the morning (pre-bathroom -/+ yes some sweat).

Also water vapor from you breathing.

Re: When somebody loses weight, where does the fat go?

#45

Post by colechristensen »

orblivion wrote: post #29
zimbu668 wrote: post #22

Earlier quoted context omitted.

From the abstract: "Most people believed that fat is converted to energy or heat, which violates the law of conservation of mass."

But not the conservation mass-energy. What's to say we're not burning off our fat in a nuclear reaction? :-D

Chemical reactions undergo the same mass loss as nuclear reactions. A fat molecule weighs very slightly more than the sum of it's parts. The resulting water and carbon dioxide products will weigh less than the reactants by exactly the amount of energy released. It's just much more difficult to notice because the amount of energy released is as much less.

Re: When somebody loses weight, where does the fat go?

#46

Post by wyufro »

corpMaverick wrote: post #33

I am confused by this... > We suspect this misconception is caused by the “energy in/energy out” mantra and the focus on energy production in university biochemistry courses. I understand from the article that chemistry (Which I can't understand) tells you that it is converted on CO2. But still. Clearly I can move because I have energy that I acquire from food. How is this wrong ?

Their point, which I agree is fairly unclear, is that the fat is not converted to energy, it's converted to CO₂ and water. That conversion releases energy, which you then use to move, but the total mass of the process is constant (conserved).

Re: When somebody loses weight, where does the fat go?

#47

Post by yetihehe »

arkh wrote: post #13
JoeAltmaier wrote: post #7

Earlier quoted context omitted.

Exercise makes more sense! Breathing hard == losing weight!

It's easier to eat less calories than exercise.

Have you tried it? I did, it's easier only for some time. After you lose about 6-7% of your body weight it's very hard to eat less, your whole behaviour changes.

Re: When somebody loses weight, where does the fat go?

#48

Post by leshow »

adekok wrote: post #38
mikeash wrote: post #4

For anyone coming straight to the comments looking for an answer to the question: it turns into CO2 (and a bit of water) and you breathe it out. When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.

2 pounds a day. That's how much CO2 you breath out, and the hard limit for weight loss. You can lose more than that, (see boxers before a weigh-in), but that's all water loss, and is temporary. And, with a strong likelihood of death.

I'd suspect the more exercise you do the more that number moves up, you'd be breathing harder. I'd hesitate to try and put a 'hard limit' on anything like this.

Re: When somebody loses weight, where does the fat go?

#49

Post by beardbandit »

StevePerkins wrote: post #37
Zanta wrote: post #12

Earlier quoted context omitted.

From the paper "Replacing one hour of rest with exercise that raises the metabolic rate to seven times that of resting by, for example, jogging, removes an additional 39 g of carbon from the body, raising the total by about 20% to 240 g. For comparison, a single 100 g muffin represents about 20% of an average person’s total daily energy requirement. Physical activity as a weight loss strategy is, therefore, easily fo…

I can't help but groan at some of the "obvious" health and weight loss platitudes that get smugly thrown around. " Calories in, calories out! " " You can't outrun a bad diet! " " Weight is lost in the kitchen! " Sure, things ultimately boil down to intake-vs-expenditure. However, it IS more complicated than that in practice . As software developers, we complain when management makes decisions based on inadequate or p…

"I can't help but groan at some of the "obvious" health and weight loss platitudes that get smugly thrown around."

On the flip side, the people that are told this are the ones that are annoyingly attempting to maintain their bad eating habits while just adding exercise, or adding fab foods, or anything really to delude themselves into thinking they can continue to eat the same way.

Re: When somebody loses weight, where does the fat go?

#50

Post by StavrosK »

JshWright wrote: post #6

An interesting corollary to this is "Where do trees get their mass?" Veritasium has a fun video demonstrating how unintuitive this is: https://www.youtube.com/watch?v=2KZb2_vcNTg

I love that you used the word "unintuitive" rather than imply that people were uneducated for thinking it. Good way of thinking about knowledge.
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