A lot of the time, CICO sucks people are using some other metric that, for them, ends up being basically a proxy for calories. I think similarly, when people totally change their diet (going low carb or keto or whatever), it basically amounts to a wholesale reevaluation. The end result of that will generally be eating less calories.

To me, all of this is basically fine. If someone finds an effective way to trick themselves into eating fewer calories, that's still a win.

I'm referring here to people who are themselves losing weight, not the hucksters.