Claudette - I'm guessing it's basically the 'magic knickers' material - not really restrictive like a proper corset, just sculpt slightly.
the top and the skirt are bigger than they should be to create the illusion.
She's not an 'unrealistic' body shape, shes a real woman - for a lot of woman it's a perfectly realistic body shape. It's so stupid to suggest she's creating an unrealistic goal for all woman, some would never be able to look like that, lots will if they want to.
No one ever looks at pictures of overweight woman and say they are worried impressionable girls will think it's a desirable bodyshape, you don't like the way she looks and wanted to start a thread slagging off another woman's body you don't deem to be attractive, but by suggesting that girls would stop eating because of this photo, you get to 'critically discuss' another woman's body in a way that would get you a thread full of anger if you'd started one about a woman who's body is large.