Peanut butter isn't loaded with sugar unless you buy stuff that has sugar added.  Real peanut butter (ingredients: peanuts, salt) has about 2 g net carbs per 2 tablespoon serving.  Most of the calories are from fat, but a significant fraction are from the protein.  Peanut butter (actual peanut butter, not whipped frosting with peanut paste added for flavor) is a VERY good food, as long as you're not overeating it.