What Is Blood Type Diet?

The blood type diets are diets that promise weight loss or other health advantages such as longer life based on the theory and ideology that ABO blood type is a very important necessity in determining a healthy diet.
There are several advocates of blood type diets, the most prominent being Dr Peter J. D’Adamo who claimed in his book “Eat Right For Your Blood” that blood groups are important in determining how our bodies deal with food nutrients. Consequently, he insists, that if you follow diets which are specific and recommended to your blood type, your body will absorb and digest food more efficiently, with the result that you lose weight, prevent diseases and have more energy and so distinct diets are recommended for each blood type.

What You Can Eat As Recommended By D’Adamo
Eating for Types O, A, B, & AB
Type O blood: A high-protein and meat based diet. For example; vegetables, beans, fish, dairy and poultry.
Type A blood: A vegetarian-based diet like vegetables, fruit and whole grain.
Type B blood: A varied diet that includes vegetables, meat, grain and dairy.
Type AB blood: Can eat foods which have been recommended for blood groups A and B.

What Do The Experts Say?
It is important to note that it is universally agreed amongst scientists, dieticians and physicians that these diets are scientifically unsupported. They have posited that our diet and our blood group have no link whatsoever. It is for this reason that qualified dietitians and nutritionists do not recommend this diet.
Pros?
Most experts do not really have nice things to say about this diet. However, this diet encourages us to eat more healthy, natural and fresh foods.
Cons?
Due to the skepticism of experts towards this theory, there have been several concerns raised to discredit the blood group diet and most of the points and concerns raised actually have merits to them. The diets recommended for all the blood groups especially O and A have excluded important and major nutrient classes of foods. This could help weight loss but excluding such important nutrients from diet would have negative effects on health in the long run.
If you still intend to give this diet a try, it is advised you try it for a short time, maybe a week or two then continue with a healthy and long term weight loss plan.
Verdict?
This diet seems to me more fiction than fact since it lacks scientific evidence to support it and has garnered a lot of negative reviews from nutritionists and health experts.
I also think it unknowingly encourages people to avoid nutritious foods in the bid to lose weight and this impact negatively on the health of an individual.