The blood type diet has attracted quite a following. It was originally popularised by naturopathic physician Peter D’Adamo in his book, Eat Right 4 Your Type. The book became a New York Times best-seller and sold over 7 million copies worldwide. Dr D’Adamo claims that most of his patients have experienced positive results following this diet in just two weeks, such as an increased energy and weight loss.
But what is the logic and science behind the blood type diet? Does it work and should you try it? In this article, we break down the truth behind it as well as its benefits and risks.
Origins of The Blood Type Diet
In Eat Right 4 Your Type, Dr D’Adamo wanted to answer the question of why two people on the same diet might not experience similar weight loss results. After his research, he discovered that blood types were the key.
By learning about the evolution of the four blood types A, B, AB and O, he discovered the answers lay in a person’s genetic markers and what people in ancient times used to eat. For example, people with blood type A are descendants from grain-eating farmers. The ancestors of people with type B blood were nomads who ate a wide range of foods, while people with type O are descendants of hunter-gatherers who consumed meat. Type AB was a new evolution and an amalgam of types A and B.
Dr D’Adamo’s findings led him to create diets based on these four blood types. According to him, choosing foods that corresponded to one’s exact biological profile can make them lose weight, reduce inflammation, increase energy and lead a healthier life.
In addition, he highlighted the relation between blood types and the immune system:
Blood type A is characterised by a sensitive immune system. People with this blood type are more prone to heart diseases, cancer and diabetes.
Recommended diet: For people with type A who can digest carbohydrates well, Dr D’Adamo advocates vegetarian foods; anything fresh, pure and organic.
With a robust immune system and a tolerant digestive system, people who are born with blood type B have a high resistance to allergies. However, they’re susceptible to autoimmune disorders.
Recommended diet: A variety of foods, from fruits, vegetables and meats. Avoid corn, wheat, buckwheat, lentils, tomatoes, peanuts, sesame seeds and chicken.
People with this blood type have minimal allergies but are at risk for cardiovascular diseases, cancer and anaemia. They tend to have low stomach acid.
Recommended diet: Type AB can enjoy the foods suggested for types A and B such as tofu, seafood, dairy and green vegetables. They must limit red meat, beans, corn and smoked or cured meats.
People with blood type O have immune systems that are environmentally intolerant. They’re most likely to suffer from arthritis, asthma, hay fever and other allergies.
Recommended diet: Consume more lean meats, poultry, fish and vegetables, and fewer dairy products and grains. Dr D’Adamo says gluten is the main reason for weight gain in type O, while grains and potatoes can cause joint inflammation.
The Truth About the Blood Type Diet
For a long time, the blood type diet has been a subject of controversy among scientists. Multiple studies have been performed to confirm or debunk the theory behind it. In short, most if not all studies agree that there is no scientific evidence supporting eating according to one’s blood type.
A 2020 study by the Physicians Committee for Responsible Medicine found that the claim that plant-based foods are better for type A and less so for type O isn’t true. Doctors and physicians will recommend including more vegetables in your diet, regardless of your blood type.
The Benefits and Risks
Despite the lack of validation of the blood type diet, it remains a popular diet which many people swear by. Here are some benefits and risks.
A 2014 study by the University of Toronto discovered that while the blood type diet can’t be proven to be effective scientifically, it doesn’t mean the diet doesn’t work for some people. This is because the diet requires one to consume nutritional meals, which are crucial for health.
While the blood type diet is in no way related to Traditional Chinese Medicine (TCM), their principles are not unlike each other. After all, TCM believes that a person’s health and individual needs differ. TCM physicians would evaluate your body constitution, lifestyle and external factors before recommending specifically tailored herbs or a diet that is suitable to their condition or issue.
Just like the blood type diet, TCM also acknowledges the connection between eating well and invigorating blood. According to TCM, the blood’s functions are:
- To provide nutrients for the organs, tissues and meridians
- To nourish skin, bones and muscles
- To maintain healthy body movement and sensations
The blood type diet can be too restrictive. If you can only eat certain foods, you might lack the vitamins and minerals from other food groups. Those who still want to try this diet might have to consume supplements for energy or immunity in addition to their daily meals.
There has been no evidence supporting the theory that eating according to your blood type is effective in losing weight. While there are many fad diets out there, what’s important is consuming fresh, whole foods. If you are unsure about what foods you should be eating, speak to a nutritionist who can help.
This is an adaptation of an article, “What Is the Blood Type Diet?”, which first appeared on the All Things Health website.
- Eat Right 4 Your Type, 2019, Blood Type and Your Health [online]. Available at: <https://dadamo.com/txt/index.pl?1001> [Accessed 5 June 2022]
- Physicians Committee for Responsible Medicine, 2020, New Study Debunks Blood Type Diet [online]. Available at: <https://www.pcrm.org/news/news-releases/new-study-debunks-blood-type-diet> [Accessed 5 June 2022]
- Science Daily.,2014, Theory behind popular blood-type diet debunked [online]. Available at: <https://www.sciencedaily.com/releases/2014/01/140115172246.htm> [Accessed 5 June 2022]
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