Difference between 不 and 没 when used with 吃.

As far as I knew, both 不 and 没 are negation for verb. You are using one of them  depends on what verb are you using.


I learnt today that there is an another interesting difference between  不 and 没 when you use with 吃.

我不吃午饭 means I usually don’t eat lunch.
我没吃午饭 means I didn’t eat lunch today.