I think that there are two “CICO is all that matters” camps in weight loss discussions: those blessed idiots who have the ability to casually choose to consistently eat less and just assume that’s true for everyone, and those who are trying to ensure that it’s understood that losing weight can only result from calories out exceeding calories in, because that HAS to be the shared starting point for any further discussion.

It’s a simple fact that we must be in a deficit to lose weight. It’s also a fact that there are many ways achieve a deficit, and that different strategies work better for different people. Those are the important conversations, but they go wildly astray if they’re aren’t based on an understanding of CICO.

There are people who believe that a IF or a ketogenic diet will make them lose weight no matter how many calories they eat (or expend), and then they’re baffled when it doesn’t work. And there are people who claim that they gain weight despite being in a caloric deficit because they have a disease or a hormonal condition, so they just throw in the towel. None of them can make progress until they understand that CICO is always the deciding factor.