Type O blood: A high-protein diet heavy on lean meat, poultry, fish, and vegetables, and light on grains, beans, and dairy. D'Adamo also recommends various supplements to help with tummy troubles and other issues he says people with type O tend to have.
Type A blood: A meat-free diet based on fruits and vegetables, beans and legumes, and whole grains -- ideally, organic and fresh, because D'Adamo says people with type A blood have a sensitive immune system.
Type B blood: Avoid corn, wheat, buckwheat, lentils, tomatoes, peanuts, and sesame seeds. Chicken is also problematic, D'Adamo says. He encourages eating green vegetables, eggs, certain meats, and low-fat dairy.
Type AB blood: Foods to focus on include tofu, seafood, dairy, and green vegetables. He says people with type AB blood tend to have low stomach acid. Avoid caffeine, alcohol, and smoked or cured meats.