Still, I wanted to share a psychological observation with you based on my own experience.
If I miss a meal when I'm not fasting my psychological and physiological experience is this: I feel weak and shaky. Feeling this, I think, "I have to eat something to get my blood sugar up."
But when I am fasting, when I'm intentionally skipping a meal, I tend not to feel as shaky or weak or needing to up my blood sugar. I'm not saying that these feelings go completely away, but that it's much, much reduced.
Basically, the mental frame--intentionally versus unintentionally missing a meal--dramatically affects both the psychological and physiological reaction to hunger.
And let me add this. I think there's a mild anxiety reaction when we find that a meal has been missed. If something happens and we don't get time, say, to eat lunch we notice our rumbling tummy or lowered blood sugar and then sort of freak out. "Oh no! I didn't eat lunch! How will I be able to get through the rest of the day!?" Which makes it all worse, both physically and mentally. I think there's an underlying hypervigilance about our bodies in relation to "hunger pains," blood sugar, and caloric intake.
But when you fast you don't have these little panic attacks when your tummy rumbles. The body-monitoring hypervigilance dissipates. Because missing the meal was the plan from the start. And so you just go about your day, not thinking about missing meals or your "energy level." You just calmly carry on.