Occasionally and for medical reasons I go one or two days with a broth plan. It includes everything and not only vegetables, but I only consume the broth. Partner and friends are happy to take care of the rest -as long as they have their home made eggs and butter sauce (with cappers).
Do I fit in size 0 clothes? Who cares. Looking great in whatever size my body stays healthy should be the goal, and as far as I've seen right now I have a good low carb outcome, a happy high fat set and proteins doing just fine the way they are.
IF comes naturally, I have an eight hours window and feel great -but I avoid this at the end of my menstrual cycle in order to avoid feeling like a massive mess, in those days I carb up a little and there it goes.
No limits, only my will and the worlds I build.