There are a number of factors that contribute to body odor from skin products to diet to medications to medical conditions. Sometimes these smells can blend together to produce a familiar odor.
Skin products such as soaps and lotions contain fragrances and the oils/spices that we eat (olive oil, curry, etc.) can add scent to our body fluids. Diabetics can have a fruity odor especially if they have extremely elevated blood sugars.
Having a peanut butter odor is something of a rarity. If you are concerned that you have an underlying medical condition, you should go see your primary care physician for a physical exam and blood work.
