The diet's main goal is lowering cholesterol, however when on the Pritikin diet you will have weight loss as well. It is really great for helping with any type of heart problem.
Foodwise, the diet sticks to fruits, vegetables, whole grain, and seafood. Processed grain, or proccessed anything, is a big no. You'll eat around six meals a day. Aerobic exercise is pretty big too, at least 30 minutes a day and weights 2-3 times a week.
It's pretty strict, almost a full out vegetarian diet, so if you have a hard time sticking to diets or giving certain things up then I'd find something a little more flexible. It's better to find a diet you know you can stick to. Good luck!