Niiiiice hips

Walking out of the store with my arms full of four giant bags of stuff I crossed the parking lot to my car. A man walking toward me slowed down, pulled the cigar out of his mouth and said, "Mmm mmm. You've got some niiiice hips." My response hovered somewhere between "Huh?" "Ooook..." and "Pfft!" I looked down to avoid eye contact and realized that there is no way this guy could even see my hips! My plastic shopping bags had formed what looked like a giant intertube around my middle.
What is the correct response to something like that? "Thanks, I work out." Or maybe, "You know it! Workin what I've got." I have no idea. And I'm still slightly disturbed.

(Photo from Google Images)