Mila Kunis

She's been on TV for years, meaning we've all watched as she grew up. She started acting at age 9 and started "That '70s Show" when she was 14, half her life ago. "Black Swan" took her from teen sitcom start to movie star and model. In a recent interview in Harper's Bazaar, she talks a bit about how that movie changed her body. She dropped 20 pounds to get down to a very low 95 pounds on her 5'4" body.

"I was muscles, like a little brick house, but skin and bones. When I gained it back, it went to completely different areas....All the weight that left my chest went to my side hip, my stomach."

The Today Show talked to a dietician about Kunis's discussion of the unexpected placement of the regained weight.

"What often happens with extreme weight loss and when you lose weight very quickly is that you lose muscle tissue," she says. "Unfortunately, when we gain the weight back, it comes back as fat."

You never lose fat cells and they don't move, so you will gain the weight back where the fat cells are, unless you're very careful to only gain back muscle. This is all just a reminder to lose weight at a steady, slow pace and not lose too much.