Picky O GroupPeople with type O blood, like my husband, are more prone to stomach problems because of the high acidic content in the stomach. So while they can digest protein well, they have to be cautious about consuming too many fats or carbohydrates. They are also known to have a sluggish metabolism so they must exercise regularly and avoid grains and heavier oils made from corn or peanut. Fresh fruits such as berries, plums, bananas and pears are beneficial as they are "friendly" with the typical stomach enzymes of those who have type O blood.