7-8 months if you stick to it religiously! Everyone weight loss rate if different I lost just over 10 stone in 7-8months (sadly have regained it all since! - trying again now)
Start exercising as soon as possible (if you are not already) then to help the inches shrink off and help with underlying muscle tone as the fat disappears. If you are new to exercise take it very slowly initially e.g. 3 x 10-15 minutes walks a day will be better than 1 x 45 minutes and just as effective initially.