Call it pseudo-science at its finest. Blood type diets offer no leg-up on weight loss, despite their popularity — seven million books in print, translated into over 60 languages.
The idea that a diet keyed to your blood type could somehow make losing weight easier is simply without merit, according to scientists who looked at the evidence, or more specifically, the lack of evidence.
Over the past fifteen years, diets based on the ABO blood group system have been promoted with claims to improve health, aid in weight loss, and decrease the risk of disease. It's an appealing idea.
The basic premise behind the diet is that a person’s blood type determines how their body handles different nutrients. Supposedly, because each blood group has a unique antigen marker that reacts negatively with certain foods, many potential health problems could be avoided by eating a diet specifically designed for a person’s blood type.
The idea that a diet keyed to your blood type could somehow make losing weight easier is simply without merit, according to scientists who looked at the evidence, or more specifically, the lack of evidence.
The theory further claims that blood type also determines the levels of stomach acidity and digestive enzymes, so if a person follows the diet for their blood type, their body will digest and absorb nutrients more efficiently and they will lose weight.
Since the diet has received so much attention, Belgian researchers decided to see if they could authenticate the claims. Using well-established life sciences and biomedical information databases and specific selection criteria, 1,415 peer-reviewed studies were located and reviewed.
Only one article was considered pertinent to the review because it looked at the variation between LDL cholesterol responses of different MNS blood types to a low fat diet, but it did not address the question as to the effectiveness of the ABO blood type diet on health outcomes. (ABO and MNS are two different types of blood group systems.)
Despite the fact that blood type diet books published in 1996 and 2004 mentioned that ABO blood type diet trials would be completed within 2 years and 12 weeks respectively, the researchers found no evidence of those trials.
“….[T]here 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. Until the health effects of blood type diets have been substantiated, the widespread claims should be clarified so that consumers are aware that the advertised health benefits are theoretical and not supported by scientific evidence,” the researchers concluded.
The review was published in The American Journal of Clinical Nutrition.
