Saw an interview with this chick about this picture the other day. She's an Australian fitness instructor.

She said the pictures were actually taken minutes apart. All she did was change clothes and put on some makeup. In the first picture she 'let it all hang out' and in the second sucked everything in as much as she could. You can also tell each bag behind her is in exactly the same position, down to material folds, in both pictures (red. brown and black).

She naturally looked more like the one on the left than on the right. It was quite interesting talking about how she'd been approached for it to be used in diet ads etc and she hadn't lost a single ounce between takes.