the windsor program comes with a little 10-day (or so) meal-guide. it seems very low-cal to me, maybe 1200 cal/day and low carb. her plan is to do pilates everyday and walk some, too. so maybe if you were previously sedentary and switch to that diet, you could lose a size... i would never be able to maintain that diet because i run and do the elliptical.
but i do like pilates. i feel stronger, and it relaxes me in the way yoga does. helps alot with flexibility, too. i think the windsor tapes are good-- especially as a supplement to a program that includes cardio and weights. maybe once i get rid of some of the belly chub i will find it helps develop a 6-pack
the "model" exercisers annoy the crud out of me though! they move like mannequinns with smiles glazed on their faces.