Some diets actually have you calorie load before starting strict programs in order to produce calorie confusion and therefore a greater loss the first week or two.
I didn't do that, nor did I cut calories/carbs by much before starting. I didn't have headaches or other problems I read about from other members during the first month. Just about everyone has a stall in weight loss around wk. 3-5 regardless of how they ate before. You'll be fine either way and if you're already feeling better from reducing certain foods even before you start IP, then that's great!
Best of luck. This is a great program and lots of threads to hang out on and get info and friendship