So what is so great about peanut butter? First of all, it has monounsaturated fat—that is the healthful fat. It is packed with fat and calories, but these are the good fats and calories. resveratrol, an antioxidant associated with cardiovascular health and longevity. On top of that, peanuts are high in protein which means that they make you feel full. You also get vitamins, magnesium, folate, and fiber.