You can. But have it be the only thing new that day, so you can see if it effects you. But make sure the peanut butter you get doesn't have sugar in it!
I LOVE my PB and apples. But I would wait and add it after the first week. Try it one day and then wait a couple of days to see how it effects your weight. If nothing happens I would say go for it!
It's a common problem in P3. It's technically not even a nut but a legume. Some can eat it and some can't. I always recommend not trying it the first week though.
well that just tells me that it is a no for P3 even though some do fine on it. Dr S said no sugar or starch so Peanut Butter would have to wait till P4, which is only another 3 weeks and in the grand scheme of things very little time.