There have been many fad diets over the years: from the cabbage soup diet in the ’60s, to the low-carbohydrate Atkins fad of the ’90s. The one thing that all the wacky diets and dieting ideas throughout the decades have in common is that they are unhealthy. Many of them will work: eating only 1000 calories a day of grapefruit will result in dramatic weight-loss; or more precisely, rapid fluid loss which is then regained after the diet is stopped.
The blood type diet, made popular by Peter D’Adamo’s book, Eat right for your blood type: The individualised diet solution to staying healthy, living longer, and achieving your ideal weight, is not much different from any other fad diet.
D’Adamo’s theory about nutrition is that the way one’s body absorbs and processes foods is affected by their blood type. This means that each blood type should eat (and avoid) different foods. Further, D’Adamo says that blood types determine how people should exercise and their susceptibility to different illnesses.
This, according to D’Adamo, is as a result of ancestral lines – where some people have hunter-gatherer heritage and should eat meat, others have agrarian (farming) ancestors and should eat little or no meat.
However, there is no scientific evidence that this diet is beneficial and no research has been done to prove that this diet works to improves health, maintain weight, or to improve wellbeing in any way.
Part of the reason that the blood type diet is problematic is because of how restrictive it is. According to D’Adamo, the following are the diets associated with each of the blood types:
D’Adamo says that this is the oldest of blood lines and as a result, people with type O blood should maintain the diet of their ancient ancestors. This means eating a lot of lean meat, poultry, and fish and avoiding grains and legumes. They should also enjoy vigorous exercise.
Supposedly type As come from an agrarian line and benefit from vegetarian diets and gentle exercise.
Allegedly type Bs have the least restricted diet and can eat almost anything but should avoid or limit carbohydrates. Type Bs should exercise moderately.
This is a modern blood type, according to D’Adamo, which should involve avoiding animal protein and exercising regularly.
The dietary restrictions don’t take taste and personal preference into account and there is no research which suggests that this diet is beneficial for the different blood groups. Registered dietician Monique Dos Santos suggests following a well-balanced diet instead. “We need to eat from each food group rather than being limited by our blood group,” she stresses.
It is important to discuss any dietary changes with a doctor or dietician to ensure that you are eating a healthy, balanced diet.