Celebs are under a slew of scrutiny about their bodies, so it's not surprising that their weight loss can be pretty extreme at times.
Whether or not these famous faces were even overweight to begin with (many looked great with meat on their bones) is up for debate, and for some celebs, their weight loss was more dramatic than healthy.
Some looked a lot better (get it done, Kelly Osbourne!) while others looked gaunt and sick (Matthew McConaughey, we missed your muscles -- we're glad they're back) following their strict regimens. In any case, for some stars, their fluctuating waist lines provided some of us with guilt, some of us with inspiration and all of us with intrigue. Take a gander at the most dramatic celeb slim downs below!