I'm not entirely certain, but I think you and I are agreeing here on the essential point I was trying (though perhaps not very well) to make. As you point out, the body is such an incredibly complex system with many processes which can malfunction or be inefficient that we can almost certainly find common ground in evidence for very large differences in the relationship between eating habits and weight gain/loss in various individuals without resorting to throwing out the entire concept of how the body is fueled or the fundamental principles of physics.BlackSpinner wrote:The body is not a simple system. It has storage capacity and it has a variety of processes - some of which are efficient and some which maybe are not. You can eat a lot today and not move and do a lot tomorrow while eating very little. It is also self adjusting for environmental factors (which includes emotions). I am sure over a life time calories = calories out, including the decomposition, I doubt many people want to consider the energy given off in their cremation/ decomposition when thinking about their diet.
I have no problem with the proposition that some people can eat like a pig, do practically no exercise, and not gain a pound because their body burns it off or otherwise dispenses of the excess in some form other than fat production, while other people eat a single lifesaver over their starvation threshold and it goes entirely to fat and which their body refuses to use for anything short of imminent death from starvation. In fact, I think that is quite likely. It just seems like these discussions get sidelined once someone raises the claim that "calories in vs calories out" is therefore invalidated.
Of course, I may be wrong, and for all I know there really is some argument I haven't seen explaining how someone might be able to consume 300 calories a day while using 900 to stay alive and not lose weight or starve to death. I've been operating under the assumption that what is really being argued is that someone eating 1200 day and using 1200 a day to stay alive can potentially reduce their intake to 1000 a day and have their metabolism slow to only using 1000 a day in response and thereby seriously limit caloric intake without any corresponding weight loss (and a lower energy level that would make exercise harder). In which case I entirely agree... with the technical caveat that since 1200 - 1200 = 0 and 1000 - 1000 = 0, the calories in/calories out formula still holds and explains the 0 weight loss in both scenarios.
