Eating according to one's blood type is very important, because what nutrition one needs also depends on the type of blood. Different studies have been done and different diets have been suggested for people with different blood group. Here the discussion begins for diet by blood type that means suggestion of food according to blood type.

Diet by blood type 'O':- this is the most common blood group found. People with blood group 'O' have high acid content in their stomach, which helps in digestion of food and increases metabolism. Diet suggested for this blood type is a high protein diet and low carbohydrate diet. They are suggested to have more soy meat, fish and soy poultry (excluding egg), and fruits with alkaline nature are suggested for them like berries. They should avoid consumption of dairy products and eggs; they should also avoid whole wheat, beans legumes and grains. It is suggestible that people having 'O' blood group should work out regularly.

Diet by blood type 'A':- people with this blood type have thicker blood as compared to other blood types and they also have a sensitive immune system. Their diet should be high carbohydrate and low fat diet. Diet of these people should be more of vegetarian diet and low non-vegetarian diet as it is difficult for them to digest meat due to less stomach acid. They are more likely to catch the heart diseases and diabetes at an early age. They should rely more on organic and fresh food. Vegetables and fruits are best for them, as they are good suppliers of minerals, enzymes and antioxidants. They should also avoid dairy products and animal fat. Cereals and grains are suggested. Beverages are suggested to them, which help them in increasing their stomach acid.

Diet for blood type 'B':- this blood type is the one, which can digest almost every type of food. They have the most tolerant digestive system. They can resist many modern day diseases like heart disease and cancer. They are highly active people. However, they are more likely prone to immune system disorder like lupus. They can very well enjoy the pleasure of dairy products, but it should not be like that, they are consuming it daily as dairy products contain high fat ratio. They are not advised to have peanuts, and tomatoes should be avoided as well completely. Blood group 'B' should avoid wheat if they want to lose weight; they should also avoid corn, lentils and chicken in order to stay healthy. Corn causes weight gain in type B thus they are suggested to have a balanced diet.

Diet by blood type 'AB':- this blood type is a combination of type A and type B. It is a very rare blood type and only around 5% of world's population consists of this blood type. Diet suggested for them is a type that includes diet of both A and B; they can have dairy products and grass fed meat. They are advisable to avoid chicken. They can have tomatoes unlike blood group B. People of this blood group should rely mostly on vegetarian food.