If it were me, I'd jump into Atkins cold turkey from IP. I'd probably start with lower fats at first though, could be a bit rough on the digestive system at first and stick to your walden farms dressings n such for awhile. I use those even while on Atkins. A friend of mine is on IP and has lost a decent amount of weight in the last few months by doing so. I've considered looking into IP, but after seeing the cost involved I stuck with the Atkins plan. Not sure how it plays into IP, but protein is suppose to build hair, nails, etc. I'd look into adding some supplements to your diet (after talking to your dr of course.) I take nettle leaf, biotin, and a green algea/ spirulina/ stuff called f2 supplement from www dot optimumchoices dot com ( no financial interest) and have seen some great changes just from the f2 supplement.
Best of luck in whatever choice you make!