Many people only see a person’s blood type as important when it comes to giving blood or receiving a blood transfusion. However, some argue that eating a diet specific to a particular blood type may offer health benefits.

A naturopath called Peter D’Adamo popularized the idea that a diet based on blood type could help a person achieve good overall health and reduce the risk of developing certain diseases.

However, research on the effects of a blood type diet is scarce, and the studies available have not proven its effectiveness. For example, the authors of a 2014 studyTrusted Source concluded that their findings did not support the claims that a blood type diet provides specific benefits.

A 2013 review of data relating to the blood type diet also found that no evidence is currently available to verify the benefits of this eating plan.

In this article, we explain why some people believe that their blood type should influence their diet. We also look in more detail at the proposed benefits of eating for the O positive and negative blood types and discuss which foods a person following this diet should eat and avoid.