There are so many crazy diet fads, and it seems like a new one shows up every day. It can be tough to know which ones are real and which ones are nonsense. One of these diets is the blood type diet. But what is the blood type diet? The diet actually has its own website, which claims to be "the most popular personalized diet system in the world." That's a large claim, but, of course, there is likely bias there. 

The History

"Eat Right 4 Your Type" was published in 1996, and introduced the blood type diet. The title of the book is another name for the diet. Its author, Dr. Peter D'Adamo, went to a school of alternative medicine. His father was the one who first had the idea of a diet influenced by blood type, and Peter decided to prove his father's ideas with research. His website notes he's a naturopathic physician, author, and researcher-educator, among other things.

#SpoonTip: Naturopathic physicians combine nature with modern science and focus on holistic healing.

Dr. D'Adamo says, "When we discuss 'diet,' we are not necessarily talking about a weight loss plan, that's a side benefit to following this plan. We are actually discussing diet in the more traditional sense, meaning a way to eat." 

This can be important to keep in mind, as the thing we associate with most diets tends to be weight loss rather than lifestyle choices. It can be confusing because the Blood Type Diet website does tend to focus on foods due to their weight loss/gain properties, but it does offer other information as well.

The Breakdown

Andrew Zaky

The blood types are A, B, AB, and O, and each type has certain foods that they should avoid, according to this diet. The website goes into much more detail, even including lifestyle tips. This Spoon article also gives a quick run-down of the diet. Here's a summary of information related to each blood type. 

A: People with this blood type do great with a vegetarian diet. Sensitive type As should eat their food in the most natural way that they can.

B: Foods that should be eliminated include corn, wheat, buckwheat, lentils, tomatoes, peanuts, and sesame seeds. Chicken should also be eliminated and can be replaced by foods such as lamb, goat, and rabbit.

AB: This blood type should stay away from caffeine and alcohol (two things that every college student lives on), particularly in stressful situations. The foods they should include in their diet are tofu, seafood, dairy, and green vegetables for weight loss.

O: For this blood type, simple carbs, like grains, are easily converted into fat. Many grains also cause unwanted inflammation and auto-immunity.

Is the Blood Type Diet Safe?

carb, eating, salad, pasta, penne, vegetable, sauce
Caroline Ingalls

While the diet is not harmful, it isn't helpful either, and not based on scientific evidence. A few reasons why it should be avoided are that it accounts for ethnicity (which is weird), it isn't actually individualized (blood type is one thing but it doesn't account for things such as medical history), and there is little science backing it up.

Kelsey Miller details her own experience in an article for Refinery29, and how she was instructed to follow it by a nutritionist (she also notes that anyone can claim the title "nutritionist"). In the article, she explains that the blood type diet did not actually do much for her other than make her eat meat again, as she was a vegetarian. It's basically all hype.

She also shares this quote from Dr. Ruth Kava, “It’s just a really cool idea that has no substantive support. There's no consistency, no logical rationale for this diet.”

Some people, however, still take to this diet. One Spoon writer actually tried the diet for herself and found the results to benefit her.

So the next time someone asks, "What is the blood type diet?" you can direct them here. It's basically what it sounds like; people follow diets based off of their blood type. Is it effective, though? That seems to be a "no" more often than not, although some claimed it worked for them. This could always be a placebo effect, or maybe their diets worked for reasons unrelated to their blood type. The blood type diet is a controversial one, but for the most part, seems harmless.