Peanut butter is considered healthy by many in terms of the protein and fat content, but the problem is that it is very high in omega-6 fatty acids.
We need to consume Omega 3 and Omega 6 fatty acids in a 1:4 ratio, but most Americans are consuming them in a 1:25 ratio due to refined oils and other processed ingredients in our packaged food (and fast food).
Peanuts are also stored in moist silos which can cause them to grow a type of fungus called aflatoxins and these affect the health of your gut. It competes with probiotics (the good bacteria) which are essential for gut health. Peanuts are also a common allergen and linked to food sensitivities, leaky gut syndrome and a slow metabolism.