Like all nuts, cashews are paleo-friendly, but you should always be careful not to eat too many of them. These little seeds have plenty of monounsaturated fat, and they aren’t as high in polyunsaturated fat as other nuts, such as almonds. On the other hand, cashews contain more phytic acid than most of the other nuts and seeds in the world.
Paleo and Phytic Acid
Phytic acid is an anti-nutrient which binds to minerals, preventing their absorption by the body. It can cause digestive issues in many individuals and even lead to some nutrient deficiencies. Soaking, roasting, and sprouting are two ways to reduce the phytic acid content of your raw cashews, but they are not fool-proof. So although you can include cashews as part of your Paleo lifestyle, be sure to eat them only in moderation.
Mark Sisson provides the pros and cons of cashews on his blog.