I'm in a forum with a lot of people who eat Coconut Butter, which is also high in monounsaturated fats. We have all learned not to eat it at night, because it really does increase your metabolism noticeably, so much so that it can be hard to sleep. But, yeah, you don't want to use PB that has sugar in it. Completely stops your fat burning mechanism by turning off glucagon production and increasing insulin production.