I have a similar story. I made major lifestyle change. But the thing is, I have got back to eating carbs and retained all the benefits (i.e. clear headless and energy all day long). Bear in mind by carbs I mean whole grain. But still, I wonder if macros are really the culprit and if keto is not placebo on top of something else (at least for me). Maybe it has something to do with insulin and glucose metabolism.