> - enough fat in my diet (it means a lot of fat)
> - enough water
>
I've also found enough water to be very important to my mental state of
well-being.  For some reason, I tend towards dehydrated, even if I am
eating enough carbs to stay out of ketosis.  But I've never considered
fat, except to consider sufficient amounts of omega-3 fatty acids.

Could it be that by eating plenty of fat in general you are getting
sufficient amounts of omega-3's, and otherwise, you aren't?  Or do you
find that any kind of fat will work?

I've also noticed, that, like many people, and perhaps a bit more
pronounced in my case, I tend to start feeling a little down if I
haven't eaten enough food in general.  I will get this before I actually
get hungry.

Erik