In my experience your body "learns" when you normally eat and makes you hungry/cranky at that time. You can re-train it, and the hunger/crankiness disappears.
For example when I started doing IM (no eating from 7 pm - 11 am) I'd get cranky around breakfast time for the first few days, and then it went, and my most productive time is now 8 am - 10:30 am.
Same thing with OMAD or regular fasting, you can retrain your body into what is normal, and you do gain better focus. You do crash fairly hard around your new eating window though.
For example when I started doing IM (no eating from 7 pm - 11 am) I'd get cranky around breakfast time for the first few days, and then it went, and my most productive time is now 8 am - 10:30 am.
Same thing with OMAD or regular fasting, you can retrain your body into what is normal, and you do gain better focus. You do crash fairly hard around your new eating window though.