Tailored Nutrition: The Myth of the Blood Type Diet

Healthy eating
Main pressant une orange sanguin - Hand preparing blood orange

Blood type diets have gained popularity over the years, promising a personalized approach to nutrition that claims to enhance overall health and facilitate weight loss. These diets are based on the theory that a person's blood type influences their metabolism and food reactions, offering specific meal plans. But what does science say about this?

What is the blood type diet?

Notebook with Drawings of Different Blood Groups and Associations Between Donors and Recipients

Popularized in the 1990s by Dr. Peter D'Adamo, the blood type diet suggests that our blood type can determine the healthiest diet for us. According to this theory, each blood type (O, A, B, and AB) has specific nutritional needs based on human evolution. For example, it claims that individuals with type O should consume a lot of animal protein, while those with type A should adopt a vegetarian diet. Type B is supposed to benefit from a more varied diet, and type AB from a combination of the A and B diets. (1)

What does science say?

Two scientific researchers discussing their research work in an office

Most scientific studies have not found solid evidence to support the claims of the blood type diet. A systematic review published in the American Journal of Clinical Nutrition reviewed the available research and concluded that the evidence was insufficient to recommend these diets. (2)

Risks of Deficiencies and Diseases: The Hidden Dangers of the Diet

Following a diet according to blood type can lead to serious nutritional deficiencies. For example, individuals with type O may lack calcium because this diet recommends avoiding dairy products. Other risks include cardiovascular issues related to high red meat consumption, performance declines in sports due to a lack of carbohydrates, digestive problems like constipation due to insufficient fibre intake, and kidney complications in diabetics due to an excess of protein. This diet can also cause frustration by restricting certain beloved foods. (3)

Beyond Blood Type

While the concept of personalized nutrition is valid, scientists suggest that other genetic factors are likely more relevant than blood type alone. Genetic variations can affect lipid metabolism, insulin sensitivity, and lactose tolerance, which may be more significant for individual health than blood type. (4)

From Your DNA to Your Plate

Two hands holding a strand of drawn DNA

Nutrigenomics, studying how our genes affect nutrient response, offers more accurate perspectives for tailoring diets. Unlike diets based on blood types, which lack concrete evidence, nutrigenomics relies on solid scientific studies to adapt nutrition to individual genetic characteristics. (4)

Take, for example, lactose, the sugar in milk. Some people have a gene variant that allows them to digest lactose throughout their lives, meaning they can drink milk without issue. Others have a different variant that causes them to lose this ability after childhood, making them lactose intolerant. (4)

Towards True Personalized Nutrition

It's clear that science does not robustly support blood type-based diets. For personalized nutrition aimed at improving your health, consulting a registered dietitian can provide tailored advice based on your needs, including biomedical analysis and genetic testing if necessary. (4)

Take the first step towards better health, book an appointment with a dietitian today. Our experts are ready to guide you towards a diet that respects your unique needs, preferences, and lifestyle.


  1. Ms, J. L. (2023, December 4). The Blood Type Diet: An Evidence-Based Review. Healthline. https://www.healthline.com/nutrition/the-blood-type-diet-review#foods-to-avoid 
  2. Cusack, L., De Buck, E., Compernolle, V., & Vandekerckhove, P. (2013). Blood type diets lack supporting evidence: a systematic review. The American Journal of Clinical Nutrition, 98(1), 99–104. https://doi.org/10.3945/ajcn.113.058693 
  3. Baribeau, H. (2021, February 9). Régime groupes sanguins. https://www.passeportsante.net/. https://www.passeportsante.net/fr/Nutrition/Regimes/Fiche.aspx?doc=groupes_sanguins_regime 
  4. Garneau, V., Dt. P, M. Sc., Vohl, M.-C., Ph. D., École de nutrition, Université Laval, & Centre Nutrition, santé et société (NUTRISS) — Institut sur la nutrition et les aliments fonctionnels (INAF), Université Laval. (2024). Utilisation clinique de la nutrigénomique et de ses tests (p. 3). https://odnq.org/wp-content/uploads/2024/02/Guide-Utilisation-Clinique_Nutrigenomique_2024_Final-Interactif.pdf 
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