Blood type O ancestors were aggressive predators. D'Adamo claims that today's type O's are characterized by being energetic extroverts and leaders with a keen ability to focus. But blood type O's, D'Adamo reports, are also prone to anger, hyperactivity and impulsiveness when under stress. When this leads to poor diet, lack of exercise and other unhealthy behaviors, type O's may experience negative metabolic effects, such as insulin resistance, hypothyroid and weight gain. Type O's are also predisposed to certain illnesses, including ulcers and thyroid problems.
Pack in the Protein
Type O's do well on a high-protein diet of lean, organic meats. The best sources are beef, lamb, mutton, veal and venison as well as cold-water fish such as cod, herring and mackerel. But blood type O's can eat any meat, except for bacon, ham, pork and goose, and any fish or seafood, except for barracuda, pickled herring, catfish, smoked salmon, caviar, octopus and conch. Blood type O's digest and metabolize meat easily, and vegetarian diets are not advised. Seafood, which is a rich source of iodine, is beneficial for type O's because iodine helps stabilize thyroid function.
Choose Vegetables Carefully
According to D'Adamo's diet guidelines, type O's should not eat certain vegetables, including mustard greens, cabbage, cauliflower and brussels sprouts because they interfere with thyroid function. Blood type O's should also avoid alfalfa sprouts, shiitake mushrooms and fermented olives, which can irritate the digestive tract. In addition, their mold content can worsen type O hypersensitivity problems. Eggplant and potatoes should be avoided because they can bring on arthritis in type O's. Type O's should not eat corn because it affects insulin production and can lead to obesity and diabetes for this blood type. Beneficial vegetables for type O's include kale, collard greens, broccoli, romaine lettuce and spinach, since they provide vitamin K. Vitamin K assists in blood clotting, and type O's are missing certain clotting factors. Type O's can also eat artichokes, chicory, dandelion, garlic, horseradish, leeks, okra, onions, parsley, parsnips, red peppers, sweet potatoes, pumpkin, seaweed and turnips.
Fruits to Enjoy
The best fruits for type O's are plums, prunes and figs, which help balance the acidity of the digestive tract to prevent ulcers. Type O's should avoid melons, such as cantaloupe and honeydew, which D'Adamo says can contain mold. Type O's should also avoid oranges, tangerines, strawberries, blackberries and rhubarb because they can further irritate a type O's naturally acidic stomach. Type O's should not eat coconut due to extreme sensitivity to the fruit. All other fruits are considered neutral for type O's.
Other Foods for Type O's
Type O's should strictly limit dairy and eggs, but they can have butter, farmer's cheese, feta, mozzarella, goat cheese and soy milk. Olive and flaxseed oils are beneficial for type O's, and canola and sesame oils are allowed, but corn, cottonseed, peanut and safflower oils should be avoided. Type O's should avoid all wheat products. Essene breads, made with sprouted grain, are beneficial for type O's, and amaranth, barley, rice, kamut, kasha, millet, rye and spelt are allowed. Pumpkin seeds and walnuts are most beneficial for type O's, but any nuts and seeds are allowed except Brazil nuts, cashews, peanuts, pistachios and poppy seeds.