I started off with a 500 calorie a day diet, I lift weights, walk, box, jump rope, and do normal workout videos, I've dropped about 100lbs in a few months, but it is not very healthy, since then I bumped my diet up to 1400 to 1500 calories, which may seem like a lot, but if you keep up the hard work and exercise you will lose it more slowly, but it will be more natural and much safer. I guess I would suggest starting off with that many calories to give your Metabolism a kick in the ass so that you can eat more and still lose more weight. I also take Vitamin B which kicks your Metabolism into high gear, and suck down green tea, it's got egcg or whatever to make your heart work harder to burn more. Hell if my former fat ass self can kick the bad habits you can to, I weighed 320 pushing a 48 inch waist wearing a 4xl shirt, now I weigh about 215, 38-40 waist, and almost down to fitting into a XL shirt comfortably. I'm still going though, my goal is 180-190lbs and a 36 inch waist, and to fit nicely into a XL shirt.