Khloe's On The "Subway Diet"

Hey, it worked for Jared, looks like it's working for her, too!

Our fave newlywed indulged in a foot-long at the fast food place, where she wasn't so fast as to not pose for a few pix with fans.

Jared better watch his back because Khloe might be a better -- and hotter -- spokesperson for the chain!