I lost 50 lbs doing this with no changes to diet/exercise. I used the protocol defined over at hypothermics.com
Basically, I didn't sleep with a blanket, didn't use hot water in showers, and made sure that I was immersed to the neck and moving in 75 degree F water for at least 20 minutes, at least 5 days a week, for three months. Progress stopped when the water got warmer, the weight has stayed off for nearly two years with literally zero effort on my part.
I also tracked my diet for a week or so before starting (generally, I eat a lot of the same stuff, so it was mostly making sure I was doing what I thought I was doing) and made sure I didn't change it at all, which is probably important, because I could see someone compensating for the calorie expenditure with more food if you're not conscious of intake.
I firmly believe that "cold water immersion, walking at a leisurely pace for a few hours, and building healthy eating habits" could go against Jillian Michaels and win, with less stress and fewer orthpedic injuries.
That said, a friend of mine dropped 20 lbs of fat and put on 10 lbs of muscle on the V-Diet, and I just finished my first week on it for "teh funz" so we'll see.
To add, I am an Indigo-3G user, I exercise regularly, and was doing both at the time.