The theory behind the eat right for your blood type diet is that people with different blood types process food differently. According to the theory, individuals adhering to a diet specific to one's blood type can improve health and decrease risk of chronic illness such as cardiovascular disease.
What exactly is the blood type diet?
Dr. D’Adamo (the primary promoter) lays out 4 different diets, one for each of the blood types there are 4 blood types, and therefore 4 diets recommended in the book.
Type A: The agrarian or cultivator. Blood type A people who should eat plant rich diets with no red meat. Type A diets should most resemble a vegetarian.
Type B: The nomad. People with blood type B should eat plants, and can eat meat (except chicken and pork), and some dairy. They should avoid wheat, corn, lentil, tomatoes, and a few other foods.
Type AB: The enigma. This person is a ‘mix’ between types A and B, and should eat a diet rich in seafood, tofu, dairy, beans and grains. However, they should exclude kidney beans, corn, beef and chicken.
Type O: The hunter. People with blood type O should eat high protein diets that are rich in meat, fish, poultry, some fruits and vegetables, but limit grains, legumes and dairy (sound familiar Paleo people?).
This eating plan has become so popular in Uganda and globally. Why? Many reasons. But what I have come to realise is that most people who end up exploring this eating style, do so because they are looking to find a solution to some kind of health or wellness challenge or they are trying to avoid one.
It may be that they are trying to lose weight or have not been successful on other plans. It may be that they have diabetes, hypertension or some other chronic disease. Or perhaps they have some kind of symptom that makes them unwell such as bloating, heartburn, gas, headaches, fatigue, pain, poor sleep or general weakness. Usually someone is looking for a solution to a problem. But other reasons are that they just intrigued by this new idea that maybe science has discovered a hidden secret to healthy eating that was previously unknown. While a few people have been sold onto the diet based on fear that if they don’t follow it, they could be harming or even poisoning themselves.
So, let me start by asking some questions.
Do you think, that all the health problems we are seeing (especially chronic diseases and weight problems) and the decline in our health is related to our blood groups? Is it possible that because we are not eating for our blood groups, we are harming our bodies and therefore seeing an increase in health challenges more than ever before?
My personal answer to both of these questions is NO.
First of all, everyone person on the planet has a blood group. That is for sure. Either O, A, B or AB. Your blood group is determined by the blood group of your parents and you most likely have a blood group similar to one of your parents (although it could be different). But in Africa and Uganda in particular, most people do not know their blood groups. I am not sure if you know yours. Our parents may know their blood groups but our grandparents are unlikely to have known theirs. And they ate food without knowing their blood groups.
What we know is that many of our grandparents and the generations before them, lived long and healthy lives, many living into their 90s and hundreds. They were much healthier than most people are today. They for sure did not eat for their blood group (and remember they must have had a blood group). So, logically it cannot be that eating for blood group was a significant contributor to their health and longevity and clearly it means you can be healthy and live a long life without having to eat for your blood group.
If your goal is to avoid, prevent or manage health challenges, remember that health problems are not caused by eating outside from our blood group recommendations.
What this argument shows, though, is that no one should conclude that if you don’t eat for your blood group you will poison your body, destroy your health or increase your risk for disease.
What about from a nutrition point of view? how valid is this theory?
The theory takes into consideration an important aspect of nutrition; the way our body digests and utilizes the food we eat. The theory behind it is that people with a specific blood group will digest certain food better than people with other blood groups and therefore by eating food that is best suited for your blood group you will have much better health whereas if you eat foods that are not suited for your blood type your health may be negatively affected and could even increase your risk for health and weight problems.
But here are some drawbacks to this theory;
Digestion is not the only aspect to be considered when we talk about food. Factors such as the nutrient content, number of calories, the way it has been grown or reared including use of potentially toxic chemicals, hormones and antibiotics, as well as the potential of the food to cause cancer, allergies or other problems must be considered. When you consider this theory, some of these factors are not considered. For example;
Consuming more than 500grams of animal protein per week has been shown to increase risk for cancer. And this is irrespective of blood group. The blood group diet, promotes meat eating in people with blood group O. So, these people are encouraged to eat more meat. Have they been told that this could increase their risk for cancer even if they can digest it better?
If you have diabetes as another example, foods that make your sugar rise faster will be a problem to you even if you are eating that food based on the recommendation of your blood type.
Foods high in toxins must be avoided at all cost as the risk of getting a disease or health problem is higher from the toxins than eating for your blood type.
How practical is it to have to figure the food that is to be eaten for your blood type, especially if you consider a home setting where the residents have different blood groups. I know a family where the parents are blood group O and AB and the children and blood groups B and A.
What about on a scientific level, what does the research say about eating for your blood group?
Multiple scientific reviews and studies done, have just not shown any evidence to support this theory. I have highlighted a few here
Research done by Canadian scientists showed that there is no evidence to support the claims of this theory.
‘Based on the data of 1,455 study participants, we found no evidence to support the Blood Type Diet theory,’ said the senior author of the study, Dr Ahmed El-Sohemy, Associate Professor at the University of Toronto. ‘The way an individual responds to any one of these diets has absolutely nothing to do with their blood type and has everything to do with their ability to stick to a sensible vegetarian or low-carbohydrate diet,’ he added.
What these researchers discovered was that the associations they observed between each of the four blood type (A, B, AB, O) diets and the markers of health are independent of the person's blood group.
A review in the American Journal of Clinical Nutrition (2013) identified 1,415 articles that may be able to shed some light on the blood type diet, and they concluded the following:
There is currently no evidence that an adherence to blood type diets will provide health benefits, despite the substantial presence and perseverance of blood type diets within the health industry.
The Norwegian society of nutrition also conducted a review and a gave a report into the theory. (By the way, Dr. D’adamo is also Norwegian)
According to the report, "The blood type diet is promoted and justified in the book by supposed scientific arguments, yet the author takes no pains to prove his ideas, just presenting them simply as facts, taking advantage of people's ignorance of biology.There should be no doubt that the author had practiced in Norway, as opposed to Connecticut, where he would be in violation of the so-called Quack Law."
From a scientific point of view, really there is no evidence to support this theory
What principles do I recommend?
The principles of healthy eating should be based on the following guidelines
We should eat a diet that is based primarily on plant foods (at least 90 percent plant based)
We should endeavour to eat whole, fresh and live foods that are grown ore reared in organic settings, free of chemicals, antibiotics, growth hormones and other toxins
We should eat mainly unprocessed and refined foods
We should eat the type of food that was eaten by people who lived long and healthy lives (what our forefathers ate) because their diets worked.
We should not follow eating plans or diets based on popular movements, big words and scientific theories. It is results and proven science that we want to follow, now just any given explanation that sounds scientific.
In conclusion, I would like to say that the theory of eating for your blood type/group is well intentioned. It hopes to help people by encouraging them to eat food that their bodies will handle better. However, this theory although convincing, falls short scientifically and nutritionally. It has been shown that there is no added benefit to following this plan and I totally agree with this point of view.
While there may be small benefit out of this eating plan (i.e. that across all blood types, the eating plan generally recommends healthier foods in each food category and so in essence if you select those foods, you are likely to be selecting healthy options) people should know the other potential drawbacks with this diet plan.
Someone should also know whether their objective will be met or not by following this plan. If you are looking to lose weight, feel better, and manage or prevent disease, then simply following healthy eating principles will offer superior results (that have been proven) while reducing on the complexity of having to navigate through this eating plan. Eating healthy is superior and simpler to following this type of eating plan.
If on the other hand, you have understood healthy eating principles and know how to select your food well based on its health promoting, disease preventing and longevity benefits, then you can go ahead and use the knowledge you have to pick out from the blood group diet what will be beneficial to you and leave out what will not.
My hope is that this article has shed some light to make it easier to navigate this confusing subject of whether to eat for your blood group or not.
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Wishing you great health and happiness.