Is it possible that PMS cravings were some sort of adaptation to help our foremothers survive/prepare for having a baby/etc?
Good theory, but . . .
By the time you have PMS, the chance of pregnancy is GONE. If the cravings occurred BEFORE ovulation or during ovulation, that would make sense. My cravings (and they may be whacky because of PCOS) happen right before the menses, not when the ovulation is supposed to have occurred.
I remember reading that you actually burn more calories in the days leading up to the menses, so that may explain the munchies. But I also crave certain types of foods--salty foods and chocolate--which may be depletion of sodium and magnesium at that point in the cycle.
One time I made (before Paleo!) a pasta with anchovies on it. I thought it was great, but my husband looked me in the eye and said "Next time you have PMS, eat whatever you want, but don't make ME eat anchovies." LOL!!!