The Scientific Argument Against Blood Type Diets
Blood type diets have been in vogue for several years now and have generated significant incomes for many a ‘nutritionist’. The founder, Dr. Peter DAdamo proposed that blood type is directly related to how our bodies react to certain foods, and that you should eat a diet specific to your blood type for optimum health and weight maintenance. There are a slew of celebrities who swear by it along with many big names in the nutrition field. As popular as it may be, the blood type diet, like so many others lack any credible foundation in scientific fact. Science is often absent in almost all the literature promoting diets and nutrition, and one of the greatest downfalls of our time is that it has become very difficult for the average person to differentiate between scientific facts and product promotion. However, by understanding the science of how our different blood types came to be, you can’t help but be amazed at how misleading and how ridiculous the idea of eating for your blood type really is.
The premise of blood type diets is that blood types somehow evolved as we did as a species. The theory, put forward by Dr. D’Adamo and bold type proponents is that the universal blood Type O evolved first, due to our hunter gatherer lifestyle. As such, individuals with this blood type should gravitate towards eating a high protein, Paleolithic type diet. As time went on, (around 15,000s BC), Blood Type A came into being, as man switched from being a hunter gatherer to a more agricultural lifestyle. As such people with Type A blood should eat a primarily vegetarian diet. Blood Type B supposedly came into existence at 10,000 BC, when somehow some groups of humans suddenly became nomadic and were eating a diet of grains. Finally, within the past thousand years, Type AB surfaced from people who ate a wide variety of food. According to blood type diet advocates, there is research showing that a specific set of proteins called lectins interact with the different ABO blood types. The theory goes on to say that this research has found that these lectins can be incompatible and even harmful with some blood types so people with different blood types should eat different foods.
Fact: Blood Types Evolved Before Humans Did
Sounds pretty scientific, but only if you don’t have an understanding of biology. It is an accepted fact that polymorphism, (the different ABO Blood Types) which was discovered and categorized by Karl Landsteiner in 1900, occurred millions of years ago, not thousands of years ago. This isn’t an esoteric piece of information as the evolution of human blood types has always been a cornerstone of scientific research into our ancestral origins. One of the problems with science is that many find the terminology a bit intimidating, but I can assure you that it isn’t as complicated as it seems, and taking the time to keep abreast with findings in science make it really hard for you to fall for the pseudoscience found in so many pieces of advertising. Here is a breakdown of how blood types evolved:
The type of blood a person has is determined by alleles at a single locus at chromosome 9.[1] These alleles encode for different amino acids called glycotransferases.
In blood type A, cytosine at nucleotide site 793 translates to leucine 265 and guanine at nucleotide site 800 translates to glycine 267.
In order blood type B, the cytosine at 793 translates to methionone 265 and the guanine at 800 to alanine 267.[1]
Blood type AB occurs when both changes occur.
Blood type O is caused when an inactive or nonfunctional protein is coded.
Studies have shown that polymorphism exists in other primates as well as all anthropoid primates. [2]Given the similarities found between human blood and that of several primates, scientists are able to use what they know based on the average mutation rate that must have occurred for there to be a divergence of A and B blood types. Using those estimates, some scientists conclude that A and B types diverged at least 13 million years ago[3]. These findings completely contradict the blood type diet conjecture about blood types being fairly recent occurrences, as polymorphism seems to have occurred at least eight million years before the first ape-like man even began walking on two legs. Other studies estimate that the blood groups would have diverged 4.5 to 6 million years ago, but in spite of the differences in estimation all accounts point to polymorphism being an occurrence that predates modern man.
From these findings there is evidence that A and B may have been the original blood types and not Type O as the blood type theory claims. Type O seems to represent an abnormal mutation as a result of a defective gene as normal genes such as A and B cannot evolve from abnormal ones.[4,5,6,7,8, 9, 10, 11] Although the O blood type is common in all populations around the world [12], there is no evidence that the O gene represents the ancestral gene at the ABO locus. Nor is it reasonable to suppose that a defective gene would arise spontaneously and then evolve into normal genes.
Fact: Bacteria & Viruses Account For Differences In Blood Types In Different Populations- Not Food
Another flaw in the blood type diet theory is the idea that specific foods are responsible for our blood type variations when diversity of blood types among specific populations can be traced to an evolutionary defense against bacteria and viruses. People have either blood group A, B, AB, or O, with each type occurring at different frequencies in populations around the world. Robert Seymour and his colleagues at University College in London used mathematical models to show that this diversity is caused by natural selection pressures imposed on human populations by viral and bacterial infections [13] and not from the foods they eat. Their model reveals that if viral infections dominate a population, blood type O will be most common, whereas if bacterial infections are more common, then A and B blood types will be more frequent. Food differences have nothing to do with it.
Fact: Race Has Nothing To Do With Blood Type Or The Foods You Should Eat To Stay Healthy
That race has anything to do with blood type or what foods we eat is not an idea supported by human biology. Race in and of itself is not a biological reality. A race is a biological 
subspecies or variety of a species, consisting of a more or less distinct population with anatomical traits that distinguish it clearly from other races. This biological definition does not line up with human genetic variation as humans are extremely homogenous. In fact every one of us is 99.9% genetically identical, with most of the differences stemming from gender and individual personality traits. Such homogeneity is not commonplace among other animals, even among some of our closest biological relatives; chimpanzees have 2-3 times more genetic variation than humans, while orangutans have 8-10 times more variation.
Fact: Avoiding Modern Refined Foods, Eating Moderately & Exercising Help Everyone Get Into Better Shape- Regardless of Blood Type
In twenty years of working with people from all over the world I have found that there are very few differences in the dietary practices required to help someone lose weight or get into great shape. Differences abound in terms of preferences, which is completely cultural influences and occasionally due to certain allergies. True some populations can tolerate certain foods better than others, but at the end of the day anyone following a diet comprised of only naturally occurring foods in amounts proportional to their activity level can lose weight and get into fantastic shape if they eat and exercise consistently. There is no gimmickry, nor any instant solutions with diets that try to make things more complicated than nature intended, as change takes time, but for that to happen, we have to have faith. Not in blood type diets, Dr.DAdamo’s or Dr. Atkins, instead we have to learn to have faith in ourselves.
Kevin Richardson is one of the most sought after New York City personal trainers, and creator of Naturally Intense High Intensity Training. Get a copy of his gimmick free weight loss ebook on losing weight here.
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