You never see old, overweight female mages with bad complexions. I would figure that someone who spends all their time locked up in a dungeon experimenting with God only knows what kinds of concoctions, reducing their eyes to slits poring over endless books on their craft, wouldn't have much time or use for making sure their outfits and bodies are as eye-popping as the spell they spent years learning that does just that.

But then again, I'm no wizard, nor do I live in a feudal fantasy land, so what do I know?

canti654 said:
wouldn't have much time or use for making sure their outfits and bodies are as eye-popping as the spell they spent years learning that does just that.

You've just said the answer yourself.

See? By MAGIC they keep fit. With magic they burn away fat and keep their muscle healthy.