Does your blood type hold the key to what you should be eating for optimal health and effortless weight loss? A nutritionist digs in.

By Cooking Light
Photo: StudioLaMagica/

Choosing what to eat based on an individual's blood type is the concept behind naturopathic doctor Peter D'Adamo's best-selling book Eat Right for Your Type. Originally published over 20 years ago, revised editions of the book continue to increase in popularity.

Unique eating approach diets, like D'Amano's, are based on the premise that individuals process what is eaten differently due to traits and genetics left over from ancestors and blood type. Each blood type has different needs, as well as certain foods that should and shouldn't be consumed. Dr. D'Adamo suggests that by eating according to blood type, an individual can become healthier, reduce the risk of disease, lose weight, and even slow the aging process.

What Do You Eat?

D'Amano's book offers specific eating recommendations for each blood type–A, B, AB, and O. Each plan is different, and diet guidelines are based upon whether foods are considered beneficial, neutral, or "poison" for a specific blood type and genetic profile. Here is a quick overview of the diet for each blood type. (Related: What Happened When This Woman Went from a Low-Carb Diet to Counting Her Macros)

Type A

  • Emphasize primarily a vegetarian diet including vegetables, fruit, beans, legumes, nuts, seeds
  • Can include some seafood, fermented dairy, and minimally processed grains
  • Avoid meat, limit dairy and eggs
  • Exercise calm and focus through tai chi, brisk walking, swimming

Type B

  • Emphasize a balanced intake of plant and animal foods including vegetables, fruits, dairy, fish, and meat
  • Can have some beans, legumes, grains, nuts, and seeds
  • Avoid chicken and pork
  • A combination of vigorous and relaxation exercises

Type AB

  • Emphasize seafood, vegetables, fruit, tofu, dairy, and eggs
  • Can include some meat, certain grains and beans, and small amounts of certain nuts and seeds
  • Avoid chicken, smoked and cured meats
  • Moderate-intensity exercise and activities that release tension

Type O Plan

  • Emphasize lean meat, poultry, fish, vegetables, and fruit
  • Can include eggs and small amounts of certain lectin-free beans and grains
  • Avoid dairy
  • Vigorous or intense exercise

Negatives of the Blood Type Diet

I try to start reviews by detailing the positive aspects of an eating plan, but in this case, I think it's important to start with potential negatives. My primary concern is that there is little research to support the idea that eating for a specific blood type impacts health. In fact, a 2013 comprehensive review of research on blood type diets published in the American Journal of Clinical Nutrition concluded that "no evidence currently exists to validate the purported health benefits of blood type diets." And when I took a closer look at published articles, the majority were either opinion- or narrative-based-not rooted in evidence. (Related: Healthy Processed, Packaged Foods That Are Dietitian-Approved)

Also, recommendations for each blood type specify avoiding and limiting different nutrient-dense foods such as dairy, beans, some nuts, and seeds, poultry, and pork-an approach that seems restrictive and somewhat pointless, since there's little evidence to support that an individual can gain health improvements by eating for blood type. While I don't think this eating plan would cause harm for most individuals, proper diet planning is needed to ensure adequate nutrients like calcium, Vitamin D, iron, and vitamin B12 are consumed due to the restrictions in each plan. (Related: How Changing My Diet Helped Me Cope with Anxiety)

Positives of the Blood Type Diet

Even though there's limited research to suggest that this approach is necessary, following a blood type diet could be an improvement in overall diet quality for many. The reason is that all four plans emphasize whole, minimally processed foods and limit processed ones with added sugars, reduced nutrients and/or additional fats. In a recent experimental study where researchers examined effects that eating by blood type had on heart disease markers like triglycerides, insulin, cholesterol, and blood pressure, the study found that blood type diets did show some favorable improvements in those risk factors. However, these findings were associated with improved diet quality and not thought to be due to eating for a specific blood type. (Related: 5 Mediterranean Diet Health Benefits That Make It One of the Best Ways to Eat)

The Verdict

Blood type diets are centered around eating more whole, less processed foods-particularly plant foods-and these are things that almost anyone could benefit from. Other positive aspects in Dr. D'Amano's book include the incorporation of activity and stress reduction and not having to track calories, macros, or other numbers. As a nutrition professional, though, I can't find any benefits in eating for blood type beyond what one can get from an eating plan that includes all nutrient-dense foods.

This story was originally published on by Carolyn Williams, Ph.D., R.D.

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