Interesting note on napping

I just had an illuminating thought.

In the past, if I napped during the day, I'd get up feeling groggy.
Recently, I've noticed that if I nap, I wake up feeling alert.

Somehow, I'm convinced that it has to do with my being steady on the food and having steady blood sugar.

What do you wise ones out there think about this? Could there be a connection?
Has anyone else experienced this?

Sarit