Just reading Run The Planet, came accross this great article which you can use to give yourself permission to eay as much peanut butter as you like !
Peanut butter is satiating and satisfying... perfect for dieters - Because you will never win the war against hunger, your best bet is to eat foods that keep you feeling fed. This means, foods with protein and fiber, like peanut butter (and nuts, in general). You will feel fuller for longer if you have half a whole wheat bagel with peanut butter, as compared to the same amount of calories of a plain white bagel. The protein and fiber in peanut butter "sticks to your ribs" and is not fattening, unless you overeat total calories that day. A Perdue University study reports subjects who ate peanuts every day did not overeat daily calories (Kirkmeyer, "International Journal of Obesity", 24:1167, 2000). Peanut eaters tend to naturally eat less at other times of the day (Alper, "International Journal of Obesity", 26:1129, 2002). Plus, if you enjoy what you are eating on your reducing diet, you will stay with the food plan and be able to keep the weight off. This is far better than yo-yo dieting!