Based on the Blood Type Diet, The O blood type is the "ancient man" and oldest blood type. Going by this example, the O blood type should eat foods high in protein, fresh organic vegetables. The O blood type should avoid grains and certain types of beans.
There is not a specific diet for any blood types, this is just a fad and should not be followed. Eat a healthy well balanced diet and you should be okay.
Know it is not true at all your diet should not be based the type of blood you have. A balanced diet low in fat is the best diet. It is just a myth that you should eat mainly a vegetarian diet if you have A+ blood
People with type A blood should have a diet that consists of soy proteins, organic vegetables, and grains. Your diet should emphasize on eating vegetables, avoiding dairy products and meals with high fat.
The drlam website is great for people looking to diet around their blood types. It has a great blood type diet table that informs you on what you should and should not eat with your blood type.
People who have blood type B should consume chicken and avoid corn, buckwheat, lentils, tomatoes,peanuts, and sesame seeds to ensure that their blood sugar levels remain stable.
There is a book by Peter D'Adamo that outlines special diets by blood type. There are differences in diet, for example, people with type O blood should not eat much dairy, but people with type B blood should eat dairy.
Diet does not have a huge amount of effect on your blood type, so everyone should just eat healthy food and a balanced diet. But some people have suggested different diet for different people, for type A, fish and vegetables are suggested.
There is no scientific correlation between blood type and diet. A healthy diet consisting of vegetables, fruit, lean protein and water will benefit you and your blood regardless of type.
There are certain foods that are better for certain blood types. For example, people with type B blood type should focus on a dairy centered diet. A person with type A should focus on an organic vegetarian diet.
According to the blood diet, people with type O blood should eat lean, organic meats, fish and poultry. They should avoid foods containing grains, gluten and dairy. Diet food lists for type O blood can be found at http://www.drlam.com/blood_type_diet/blood_o.asp
Your diet should not be dependent on your blood type. There are no set dietary restrictions based on blood type. You should however eat healthy foods like fruits and vegetables since these are important for people with every blood type.
People having an A positive blood type is recommended to follow a vegetarian diet. They should also be cautious to intake very little protein and dairy products.