There's no "caloric deficit." Your body stores and oxidizes fat because it needs to get the appropriate mass from somewhere. If the body has fat to oxidize, t

There's no "caloric deficit." Your body stores and oxidizes fat because it needs to get the appropriate mass from somewhere. If the body has fat to oxidize, then there's no deficit of anything. > It doesn't make a difference what kind of calories you're intaking - your body literally does not know. You're conflating a few things here. Fundamentally, you're saying that the body doesn't contain an internal calorie counter. In that sense, you are absolutely correct. The human body, and pretty much all organisms performing respiration, does not keep track of calories in any capacity or measure mass. The only thing the body can do is delegate different kinds of mass to the places in different cells where their presence would be of benefit to the survival of the system. That's really it, though it's a bit of an oversimplification. However, if we correct "kind of calories" to "kind of mass", and drop the whole idea of the body "knowing" something, then what you are saying is fundamentally untrue. It is not controversial in any way that the cells in the human body, and all creatures for that matter, treat macronutrients differently and prioritize them in ways that are not equivalent. Yes, it's more complicated, but food composition is way up there in terms of importance.