Yes, of course the correlation/causation issue is true as always. I am sorry if I gave the impression of presenting a study or meta analysis. Not sure I understand what I did wrong (English is my second language), it was meant to be perceived as an anecdote.

I think any change you make will feed into changing other things about you.

In my case I changed only diet. This in turn changed me so that I could move more. Both of those things changed how I sleep. Which again feeds back into new changes about my mood and goals. I do not think I could have started with one of the other changes and end up here. Especially in my own circumstance.