How is CICO flawed?
Except that extremely simple mathematics that completely ignore all sorts of confounding factors such as, say, hormones, isn’t going to give anything like a useful result.
It’s like talking about the first law of thermodynamics. If the body was a closed system with known and controllable variables, that might be useful. But it’s not even close to that, so it’s not even close to useful.
However, it’s simple, and people like simple explanations.
I wish I knew. I have read everything from a few weeks to 36 hours.
I suspect it varies by person and has a lot to do with what you are eating. I think 1000 calories of, say, rice cakes will slow your metabolism quickly because your body would think you were in some serious depravation to be eating that junk. Where 1000 calories of eggs would be pretty nutritious so it wouldn’t seem like famine and would keep your insulin down so you could access fat.
Or WHEN you are eating it. Most of us skip breakfast because we aren’t hungry when we wake up so it’s the easiest meal to skip.
But I’ve read IF studies where skipping dinner is more beneficial from a blood glucose/insulin response.
Where in the CICO world does WHEN you eat come into play? It doesn’t and is therefore too simple a theory to explain our complex biology.
Janie, it’s always there - insulin response is larger and longer in the evening, versus the morning, and thus if insulin levels are a concern then as you say better to eat in the morning versus evening, if eating once a day. Higher insulin means more of the “out” part of CICO going to storage, versus being burned for energy.
Some people do have an erroneously simple view of CICO, i.e. that Out is independent of In, and that restricting the In won’t decrease the calories burned, as it demonstrably does, at times. This is not CICO itself being flawed, however.