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What? Yes it is. Your fat cells are turned into ATP via Beta-oxidation and used for cellular energy. The excess carbon from the processes is then exhaled as CO2

by devmor 3y ago

What? Yes it is. Your fat cells are turned into ATP via Beta-oxidation and used for cellular energy. The excess carbon from the processes is then exhaled as CO2 during normal respiration and the water is sweated or urinated. When you lose about 3500 calories of energy via this process, you have burned a pound of fat.

bluGill 3y ago
The fat in the cells are turned into energy, but generally the cells remain.
- devmor 3y ago
  Yes that is true, the water and lipids in the cell are extracted, but the cell stays there until its natural cell death (which can take years). That doesn't really have anything to do with the conversation though.
dekhn 3y ago
Do people who burn 3500 calories weigh one pound less? Are you sure? (that belief is mainly based on an old study where fat was removed from a body and combusted). It's been observed, with newer more accurate measures, that fat burning doesn't correlate perfectly with weight loss. From what I can tell, weight changes happen only partly due to CO2 exchange and partly due to rates of consumption and excretion. The biophysical origin (I'm a biophysicist) of weight change as a function of energy use, eating and excretion is a bit more complicated than that.
- devmor 3y ago
  Give or take, yes. Like you said, it’s a bit more complicated than that and every body is different. But burning roughly 3500 calories will result in the body weighing roughly 1lb less (accounting for food and water intake and loss). If it didn’t work this way, every bodybuilder and fitness enthusiast on the planet would have a very different approach to their diet.
- mock-possum 3y ago
  So wait if I fasted for two days, could I responsibly expect to come out the other side one pound lighter? That’d be a roughly 3600 calorie deficit.
  - devmor 3y ago
    Yes.
- insanitybit 3y ago
  Assuming that they burned purely fat for energy, what else could it be? Are you saying that it's not just fat being burned, or that 'burning' the fat is not going from '1' to '0' in terms of weight?

by devmor 3y ago

bluGill 3y ago

The fat in the cells are turned into energy, but generally the cells remain.

devmor 3y ago
Yes that is true, the water and lipids in the cell are extracted, but the cell stays there until its natural cell death (which can take years). That doesn't really have anything to do with the conversation though.

dekhn 3y ago

Do people who burn 3500 calories weigh one pound less? Are you sure? (that belief is mainly based on an old study where fat was removed from a body and combusted). It's been observed, with newer more accurate measures, that fat burning doesn't correlate perfectly with weight loss. From what I can tell, weight changes happen only partly due to CO2 exchange and partly due to rates of consumption and excretion. The biophysical origin (I'm a biophysicist) of weight change as a function of energy use, eating and excretion is a bit more complicated than that.

devmor 3y ago
Give or take, yes. Like you said, it’s a bit more complicated than that and every body is different. But burning roughly 3500 calories will result in the body weighing roughly 1lb less (accounting for food and water intake and loss). If it didn’t work this way, every bodybuilder and fitness enthusiast on the planet would have a very different approach to their diet.
mock-possum 3y ago
So wait if I fasted for two days, could I responsibly expect to come out the other side one pound lighter? That’d be a roughly 3600 calorie deficit.
- devmor 3y ago
  Yes.
insanitybit 3y ago
Assuming that they burned purely fat for energy, what else could it be? Are you saying that it's not just fat being burned, or that 'burning' the fat is not going from '1' to '0' in terms of weight?