This eating plan is explained in Eat Right For Your Type by Peter D’adamo. The basic premise is that the four blood types (O, A, B, AB) evolved at different points in history and are thus best suited to the lifestyles prevalent at those times. The four blood types have varying nutritional & exercise needs, pre-dispositions to different types of illnesses and react differently to various foods.
Peter’s father (James D’adamo) was a naturopath and clinically tested this plan for 35 years with excellent results. Peter has expanded on this work. The book includes detailed lists of which foods are good for each blood type and which should be avoided, as well as the scientific basis of the diet and an overview of each blood types nutritional and exercise needs.
However, it appears the science is not as sound as it first appears. This review from the Weston A Price foundation website, goes into it in some depth.
So much for the science – the real question is, does it work? There is no doubt at all that different people have different metabolic needs. Various experts recommend many different eating styles. Most of them have a lot of merit and work really well – for some people. Some of them have lots of elements in common, but some of them are quite contradictory. Differences in metabolic types allow for people’s varied needs and explains anomalies such as :
- why some people thrive on a vegetarian diet, while others feel lethargic and unwell
- why high protein diets cause some people to lose weight and some to put it on
- why Ayurvedic medicine says milk is very beneficial (it is for blood type B), while most people are intolerant of dairy products
The blood type diet is not an ideal metabolic diet, as it only takes one genetic marker into account. For some people, especially O types, it works reasonably well. But others, especially A types, often do extremely poorly on it. A major reason for this maybe that O types are told to eat lots of meat and avoid commercial grains, while A types are told to eat a mostly vegetarian diet, including soy which is dangerous. My opinion is that Bob McFerran’s metabolic diets are better.
If you do decide to try the blood type diets, remember this is a starting point, and individuals may be intolerant of something that otherwise would be beneficial for their blood type. It can be combined with other plans, eg. Food combining (for people with digestive problems) or the Zone (best suited to O types). One O-type ER4YT follower said “I use ER4YT to determine what to eat, and the Zone to determine when to eat it”.
Peter has a good website which includes FAQ, recipes, and a bulletin board to allow discussion between users of the plan.
These are valuable resources, but it is important to read the book first (and of course, find out your blood type). Remember, with any new eating plan, it may take a few weeks before you start to see results, so don’t be discouraged if a friend gets benefits almost immediately, but it takes you a bit longer. Also remember, if you don’t get results at all, this may not be the plan for you. For those who find ER4YT unsuitable, the metabolic diets are the next step.
The following chart gives an overview of the four blood types :