Peanut butter is ok on PP, but note it is pretty high in carbs and doesn't have the greatest proportion of fats (almond butter is better) If you find you can keep your intake to small amounts (ie its not a trigger food as suggested above) then go ahead - just make sure you get a sugar free version, or better yet go to a health food shop where they will grind some fresh (with no other ingredients).

Cheers,

Malcolm