Originally Posted by
OBoile
If you truly understood what you posted here, you'd realize that none of it contradicts calories in vs calories out.
But then, that shouldn't be surprising, since it is impossible.
All respect, but you're missing the point. Metabolic changes affect the calculation of calories out such that the idea one can "simply" balance the two is absurd. As you lose weight, the body becomes more efficient at using the calories you take on board, thus if you keep your activity and intake constant, you will stop losing weight and maybe even put some of it back on. Given that there is also a tendency to lower metabolism as we age, this balance is a constantly moving target.
Basically, even at the individual level, our data concerning calories in and the data on calories out are so subject to so many variables, that they are at best very rough estimates.
None of this stuff is simple, otherwise it would have been solved long ago.