Don't be fooled the top rolls down.  If you order the size  you want to actually help you hold your tummy in, it will be too small the the top will roll down.  I was so frustrated with this, and of course at an event when I couldn't take it off.....waste of $$.  If I'd bought a larger size to prevent the roll down of the waist, then it wouldn't have any effect on holding in my tummy.  Don't bother.  The only thing I think might get the effect I was hoping for was some sort of whole body suit, and who wants to wear something like that all day long in the heat.