Is there any scientific basis to the blood type diet?
"There had to be a reason why there were so many paradoxes in dietary studies and disease survival, why some people lose weight and others do not on the same diet or why some people keep their vitality as they age, and others do not," says Dr D'Adamo. “Blood type is the key that unlocks the door to the mysteries of health, disease, longevity, physical vitality, and emotional strength."
The doctor stipulates the following with regards to blood type and overall health:
- Medical conditions and diseases: For instance - Type O’s are at a low risk for heart disease, but at higher risk of stomach ulcers. Type A’s have a higher risk of microbial infections. Type B’s and AB’s are at higher risk of pancreatic cancer.
- Reactions to stress and stress hormones: For instance - Type O’s have a distinct ‘fight or flight’ response, resulting in an overproduction of adrenalin which takes some time to clear from the body. Type A’s produce higher levels of cortisol.
- Gut bacteria and nutritional needs: Different blood groups have different gut bacteria, as a result of evolutionary changes to eating habits. Dr D’Adamo recommends a low-lectin, non- agglutinating diet plan that “creates a hospitable environment for your ‘good’ intestinal flora” and thus reduces disease risk.
The opposing argument
One of the key attractions associated with this diet is weight loss. Like most diets, losing excess weight is the nucleus around which the entire plan is predominantly based. Improved health and reduced health complication risks follow suit as added attractive benefits.
The blood type diet is no different in this regard. The bottom line for most who have researched and offered up an opinion about this diet, irrespective of specialist area of expertise, is that any plan that promotes the avoidance of processed foods (and some carbohydrates) is good for you, no matter your blood type.
Can you lose weight? Weight loss and overall healthiness is bound to follow when reducing the intake of processed foods (and the associated calories) and is sure to help anyone achieve a better physical state. Thus, the consensus with opposing viewpoints is that overall healthy eating benefits everyone and is not blood type specific.
Depending on the type of foodstuffs incorporated in the individual diet plans, weight loss is achieved on different levels. Viewpoints therefore agree, that weight loss on this diet is achievable, but not because it specifically works as a result of blood group adaptations or influences, but rather because the diet is restrictive of certain foods.
When it comes to lowering risk of specific medical conditions, disagreement continues. Does this diet really improve your digestion ability (based on blood type) and give you more energy? A diet plan developed by Dr D’Adamo can and does seemingly contradict others that a medical doctor will develop for a patient with, for example, diabetes. One will encourage a high protein diet. Another will request that you limit or avoid dairy. A doctor may not advise a person with a chronic condition to cut out a specific food group altogether. The blood type diet is more restrictive in this sense.
Conditions such as heart disease, hypertension (high blood pressure), and cholesterol have critics up in arms too. Low-fat and low-sodium diets are essential for these conditions. Few feel Dr D’Adamo has adequately addressed this in his diet plans.
Exercise and the required amounts (whether it be of the aerobic variety or calming practices) is also still a debatable area. How much is really good for you per week?
So, yes, you may very well lose weight, feel healthier, have more energy and have improved digestion on the blood type diet. But no, there is seemingly not enough scientific evidence that substantially agrees that the diet effectively reduces risk for disease susceptibility or that this happens in any way, shape or form as a direct result of your blood type. The fact that it may work merely comes down to your own individual ability to stick to a set way of eating and exercising as part of your lifestyle.
Other downsides (for some people) are that the raw, organic and lean nature of the diet will effectively mean your choices of foods are limited, will require time in the kitchen to prepare and will be a little taxing on your purse. For the time-poor city slicker, this may not be attractive. Organic foods are also not known to be incredibly affordable, the world over. Expenses can thus add up if you choose to buy into the doctor’s range of supplements too.
So, who’s argument is most true?
The jury may still be out on this one. There’s no doubt about this, this diet and its hypothesis is intriguing. There may still be, decades after the initial publication, professionals researching and conducting comprehensive tests to either prove or disprove the notion of a direct linked to blood type groups. With so many influencing components and the complex nature of the body and its functions, this topic may be a hot debate for a while yet.
Both sides seemingly pose logical arguments. The disproving side advocates (loudly) that there is no scientific evidence. Dr D’Adamo interjects as often as possible to provide his carefully researched side of the story, which supports his hypothesis wholeheartedly. He may even agree that studies conducted thus far have been poorly designed. Blood types are a complex thing when looking at such a wide range of variables affecting the human body. This makes any research highly sensitive and incredibly complex.
It’s a constant tennis match. For many, restrictive diets with a specific purpose (like losing weight) are attractive (and often used in a short-term capacity). For others, a well-balanced and healthy diet, limiting intake of certain foods without cutting them out completely is the way to go. The bottom line, is it comes down to YOU and what you put into your body for healthy living to meet necessary nutritional requirements. We all fare differently when it comes to certain foodstuffs. Some may support Dr D’Adamo in his thinking as the fundamental reason for this. Others not. Any diet appropriate for your individual metabolism is likely to show positive effects on your overall health.
If you’re curious to try this diet, go for it. Remember that eating is never a case of ‘one size fits all.’ You may have to customise, modify and adapt any diet plan you take on to make it your own for maximum comfort and sustained commitment.
If you have a medical condition, especially a chronic illness, or even just known food intolerances or allergies, seek advice from your primary medical professional (general practitioner) before you adapt your eating habits. The blood type diet has pros and cons, and restrictions may very well impact the nature of a medical condition. It is best to not take a chance if you have a known condition which can be aggravated by food.
For the most part foods included in the diet are healthy. The general consensus is that, for the most part, it will have a healthier effect, no matter your blood type. The debate is the relevance of blood type as the dictator of the diet, and if there is an existing medical condition, whether or not a restrictive plan will negatively affect an illness.
If it works for you and you feel you can stick to it without any disruptions to your overall health, it’s not the worst way to eat. But if it (your current diet) ain’t broke, there’s no need to fix it either. Happy eating!