People born into different ancestries have different types of blood, including A, B, AB and O blood types. Because each blood type is specific to a certain time period and geographic region, the history involved in that area plays a part in what types of food each blood type should have. For example, type "O" blood is the oldest blood type, and is found in the ancient hunter-gatherers who sustained themselves on meats, nuts, seeds and fruits.
Eat more lean proteins. Select protein sources like low-fat chicken or turkey, fish or lean cuts of beef. Animal protein sources contain minerals, vitamins and proteins that will ensure that people with type "O" blood types will have enough energy to maintain their bodies throughout the day. Hunter-gatherers would eat larger portions of meat because they used meat as their main source of food.
Avoid eating large amounts of refined grains, such as white flour breads and pastries, pastas and white refined rice and cereal. These foods were not available for ancient type "O" blood types during the hunter-gatherer period.
Eat a plentiful amount of food that would have been gathered during hunter-gatherer times, such as nuts, seeds, berries and fruits. Nuts and seeds contain larger amounts of protein, which is important for type "O" people. Fruits and berries are high in vitamins and fiber, which is useful in keeping the digestive system in balance.
Eat a plentiful amount of fresh vegetables that are normally eaten raw, such as carrots, celery, lettuces and green beans. Fresh vegetables are high in vitamins and minerals, as well as fibrous cellulose that helps the digestive system. Avoid vegetables that must be cooked in order to be eaten, such as potatoes, that were not typically eaten during the hunter-gatherer time period.