For people knowingly in ketosis how do you know when you are really hungry because it turns your appetite right off? I find myself just eating because its lunch time but I'm not hungry ever!!
My hunger is honestly maybe 90% decreased while in ketosis.
I really only get hungry in ketosis when fasting for 24+ hours.
That beign said, you'll learn quickly when your body could do with a meal. It's more of an art than a science really.
You still get hungry but it is not the sudden 'OMG I have to eat right now this second!' hunger caused by dropping blood sugar. The hunger is subtle and builds slowly over hours, and even when quite hungry you can still say to your body 'We can't eat now, food is later' and it will say 'No problem' and let you get on with stuff.
Many people forget to eat in ketosis because the hunger is so subtle and they are distracted, but it doesn't really matter as insulin to low and fat flows freely from the fat cells so there is no hunger in a cellular level, that is cells are being fuelled all the time.
When I am in ketosis I sometimes forget to eat, or am just disinterested, unless it is something particularly savory. I also tend to get bored with low carb, which could be part of the disinterest, though I overall feel great despite both of those situations. It leads to very easy IFing for me.