Other than it tastes great

Lately I've been trying to eat more white potatoes instead, as they're a more nutritious source of starch, but I still get cravings for rice. When I eat it I instantly feel good - it lifts me in a way no other real food does.

But it's just pure starch, right? Pretty nutritionally void? So why does it make me feel better than potatoes, or even bananas?

I have a (layman's) theory that a depressed physiology operates better on chemically simple, energy rich foods. Or is there some micro-nutrient in rice that can't be derived elsewhere?