What About Lectin Theory

D'Adamo's lectin theory also remains unsubstantiated. Although lectins do exist in foods, there specificity remains in question. The so-called Nachbar Study showed that 29 of 88 foods tested did exhibit lectin like activity. However, it was found that almost all of these foods were not ABO specific and therefore do not support the theory that lectins are specific for certain blood groups.

Are There Any Benefits?

Dr. D’Adamo generally does not support the use of processed wheat products, heated oils, sugary foods and processed foods. He also suggests buying organic and grass-fed where possible. A person sitting down on these foods and eating more whole foods as he suggests is of course going to benefit.

Are There Any Downsides?

Although the blood type diet promotes natural eating and whole foods, there are many downsides to this way of eating, especially if it is followed over a long period of time. Some of the downsides include:

• Behavioral and psychological issues around food. Labeling otherwise healthy foods as “bad” can create issues for people around food. A healthy diet is a varied diet and there is no need to label an otherwise healthy food as bad because of an unproved theory.

• The diet does not make room for your preferences, lifestyle or specific health conditions. For example you might not like the foods on the allowed list or some of your favorite foods might be on the avoid list. Someone with digestive issues for example might be asked to eat lots of animal protein and avoid grains and suffer more with their symptoms as a result.

• Some of the foods on the avoid list for your blood type might contain amazing health benefits that you are missing out on. For example avoiding something like spinach, or avocado or red berries means you are missing out on their nutritional and antioxidant benefits.

• Some people might suffer specific health consequences as a result of following the diet. For example a person with blood type O who has high cholesterol could make their condition worse by eating lots of meat and avoiding grains and certain vegetables. A person with blood type A following a vegetarian diet might suffer a B vitamin or iron deficiency as a consequence.

• A family that has members with varying blood types will have a hard time cooking for a family with different lists of foods to avoid or eat.

Final Verdict?

People like the idea of a diet that is designed specifically for them. 

See Also: We Are What We Eat: The Effect Of Diet On Our Genes

Try it if you must, and by all means stop eating junk food and switch to a more wholesome diet. If the diet works for you, the most likely reasons are probably not related to your blood type but something else about the diet, like higher nutrient intake, reduced calorie intake or cutting out junk foods, rather than the blood type and food lectin interaction.