weight loss through fasting??

Ive been doing a lot of research, and i mean a lot!
but every site i find tells me different things e.g. Water Fasting is great for you, and you will loose weight..yet another will say 'no you will just get bigger'..

Im 185 pounds and i want to get to 125! im willing to do an extended fast of 40 days, but im worried it will all go to waste and be a waste of time? will i even loose inches and drop dress sizes? if anyone has any advice and information it would be greatly appreciated, im really confused but eager to start! Thanks x