There is obviously thermodynamic energy in food which is not absorbed in the gastrointestinal tract. Fiber is an example of this. Energy which is not absorbed is not listed on the nutrition label of food.

On a previous occasion when this topic came up, I posted this anecdote.

Now, as you might imagine, there were medical reasons for that episode. Or rather, there were concurrent medical events with no obvious connection: acute ulcerative colitis, a disease of the large intestine only. Most nutrition is extracted by the stomach and small intestine, which were unaffected. So what was going on there? What made my digestive system so inefficient for several years following the initial attack?

So there's a lot of room for variation in digestive efficiency.

(For those who know the last-resort treatment for ulcerative colitis, I'll just add that I recovered without surgery.)

Your claim that CICO is as helpful as MIMO is clearly ridiculous

What is more ridiculous about MIMO than CICO? Conservation of matter, can't argue with that.

and if you truly believe this, then supermodels eating tissue paper are more rational than you, as their beliefs will lead to more accurate predictions.

You don't get to be a supermodel unless you can stay thin. Some people can, no-one doubts that, and some people just are, without taking any effort. And I'll take Eliezer's word that nothing has worked for him over anyone's assertion that because they can't see how something could happen, it doesn't happen. CICO is only one part of the picture, and its abundantly clear from experiences of dieting that it's of little explanatory value on its own, and of practical value to only a subset of people.