Ever stood in the grocery aisle staring at a carton of eggs, wondering if your blood cells were about to stage a microscopic riot? Sounds dramatic. It kind of is. If you've spent any time in the wellness world, you’ve likely stumbled upon the AB+ blood type diet. It’s the brainchild of Dr. Peter D’Adamo, a naturopathic physician who basically set the internet on fire back in 1996 with his book Eat Right 4 Your Type. People still swear by it. Others think it’s complete nonsense.
The theory is wild. D'Adamo argues that your ABO blood group is the single most important determinant of your health and well-being. He claims that "lectins"—which are just proteins found in food—react differently with your blood depending on your type. For those with AB positive blood, he calls you "The Enigma."
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The weird science of being an Enigma
Why the Enigma? Because AB is the newest blood type, evolutionarily speaking. It’s a mashup. You’ve got the traits of Type A and Type B swirling around in your veins. This makes the AB+ blood type diet a bit of a balancing act. You have the low stomach acid common in Type A folks, but you also have the adaptation to meats that Type B brings to the table.
This creates a physiological paradox. You might crave a steak because of your Type B heritage, but your Type A low stomach acid means you can't actually digest it efficiently. The result? That steak doesn't get metabolized properly. It sits there. It gets stored as fat. At least, that's what the theory says.
Honestly, the AB type is rare. Less than 5% of the population carries it. Because it’s so uncommon, finding specific, peer-reviewed clinical trials that focus exclusively on AB+ individuals and their reaction to lentils or turkey is like hunting for a unicorn. Most of what we "know" comes from D’Adamo’s own observations and the biochemical properties of lectins.
What the AB+ blood type diet actually looks like on your plate
If you’re following this plan, your kitchen is going to look pretty specific. It’s not quite vegan, not quite paleo. It’s a middle ground.
Meats and Proteins
You’re supposed to focus on things like turkey, lamb, and rabbit. Notice something missing? Chicken. D’Adamo claims chicken contains a lectin that agglutinates (clumps) the blood of Type B and Type AB people. That’s a tough pill to swallow for most meal-preppers. You’re also told to avoid red meats like beef and pork because of that low stomach acid issue I mentioned earlier. Seafood is a big win, though. Mahi-mahi, red snapper, and salmon are considered "highly beneficial."
The Dairy Dilemma
Unlike Type A, who usually need to ditch the cheese, the AB+ blood type diet is surprisingly friendly to dairy. Yogurt and kefir are great because they provide fermented enzymes that help your digestion. But you’ve still got to be careful. Ice cream? No. American cheese? Absolutely not. Cultured dairy is your friend; processed dairy is the enemy.
Grains and Greens
Wheat is a tricky one. While most people do okay with it in moderation, D'Adamo suggests Type ABs avoid it if they are trying to lose weight. Instead, you're looking at oats, rye, and rice. Then there are the vegetables. Most are fine, but you’re supposed to dodge corn, black beans, and lima beans. Why? Lectins. It always comes back to the lectins.
Does the science actually hold up?
We have to be real here. In 2013, a massive systematic review was published in the American Journal of Clinical Nutrition. Researchers looked at data from over 1,400 studies. Their conclusion? There is currently no evidence that an AB+ blood type diet provides specific health benefits to people of that blood type.
Wait.
Before you toss the book in the trash, there’s a nuance. A 2014 study from the University of Toronto found that people following these diets did show improvements in cardiometabolic risk factors (like cholesterol and blood pressure). But—and it’s a big "but"—those improvements had nothing to do with their blood type.
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If you stop eating processed pork and white bread and start eating kale, salmon, and yogurt, you're going to feel better. It doesn't matter if your blood is AB+ or O-. Eating whole foods works. The "blood type" part might just be a very effective psychological hook to get people to stick to a clean diet.
The Lectin Factor: Fact or Fiction?
Lectins are real. They are "anti-nutrients" found in plants. Some, like the ones in raw kidney beans, can actually make you very sick. But the idea that certain lectins specifically target AB+ blood cells and cause them to clump together in your organs is a massive leap that most hematologists just don't support.
Dr. Steven Gundry, author of The Plant Paradox, has reignited the lectin debate recently, but even his work doesn't strictly align with the ABO system. It’s complicated. Biology is messy.
Weight loss and the AB+ metabolism
People usually find the AB+ blood type diet because they want to drop ten pounds. The plan suggests that for AB types, weight gain is driven by a combination of genetics and stress.
Since Type ABs inherit the Type A reaction to stress—which is a spike in cortisol—they tend to carry weight around the middle. High cortisol plus a slow-moving digestive tract is a recipe for weight gain. The diet recommends "calming" exercises like Tai Chi or Yoga rather than high-intensity interval training (HIIT), which can sometimes spike cortisol even higher in sensitive individuals.
- Avoid: Corn, buckwheat, wheat (if stalling), and chicken.
- Embrace: Green veggies, tofu, seafood, and pineapple.
- The "Secret" Weapon: Vitamin C and digestive enzymes.
Pineapple is a big deal in this community. It contains bromelain, an enzyme that helps break down proteins. Since Type ABs struggle with protein digestion, a bit of pineapple can actually be a functional "hack" for your gut.
Why people keep coming back to it
If the science is shaky, why is this diet still a thing 30 years later?
It's about identity. Humans love categories. We love being told we are an "Enigma" or a "Hunter" or a "Teacher." It makes a generic diet feel personalized. When a diet feels like it was "made for your DNA," you’re more likely to follow it.
Also, the AB+ blood type diet inadvertently forces you to cut out a lot of garbage. No more pepperoni pizza (pork/wheat). No more fried chicken. No more sugary sodas. When you cut those out, you lose weight. You feel less bloated. Your skin clears up. You credit the blood type theory, but your liver is just happy you stopped eating junk.
Real-world limitations
Living as an AB+ on this plan is hard. Go to a birthday party. There’s chicken wings and cake. You can’t have the wings (chicken lectins) and you can’t have the cake (wheat/butter). You end up being "that person" at the dinner table.
It can also lead to nutrient gaps if you aren't careful. If you cut out all red meat and all chicken, you need to be very intentional about your B12 and iron intake. Shellfish and leafy greens help, but it takes work.
Actionable steps for the AB+ individual
If you want to experiment with the AB+ blood type diet, don't just dive in headfirst and throw out your pantry. That’s how people fail.
Start with the "Big Avoids"
The biggest needle-movers for Type AB are usually removing chicken and corn. Try swapping your morning chicken sausage for turkey or lox. Switch corn tortillas for flour (if you tolerate wheat) or rice-based wraps. Do this for two weeks. See if your bloating changes.
Focus on Gut Acid
Since low stomach acid is the supposed Achilles' heel of the AB+ type, focus on bitter greens like arugula or dandelion greens before a meal. These naturally stimulate digestive juices. Or, try a tablespoon of apple cider vinegar in water.
Vary your proteins
Don't just eat tofu. If you're AB+, you have the unique ability to handle some dairy and some meat. Use that variety. Mahi-mahi one night, lamb stew the next, and a Mediterranean bowl with feta and chickpeas the day after.
Audit your stress
If you're doing 5 AM CrossFit and feeling exhausted rather than energized, your AB+ "Type A" stress profile might be crying for help. Try swapping two of those sessions for a long walk or a swim. Watch how your body composition reacts.
The AB+ blood type diet isn't a magic spell. It’s a framework. While the molecular biology of lectins clumping your blood remains unproven by independent science, the core tenets of the diet—eating whole, unprocessed foods and managing cortisol—are rock solid. Listen to your body. If the "Enigma" diet makes you feel like a superhero, keep going. If it makes you miserable and nutrient-deficient, your blood type probably isn't the boss of your dinner plate.