Blood type O is the most common blood type, with around 44% of the population having type O blood. People with type O blood are often referred to as “universal donors” since their red blood cells can be given to people with any blood type. However, those with type O blood may need to be a bit more thoughtful about their diets as some research suggests there are benefits to following a specific diet for this blood type. In this article, we’ll take a closer look at the research behind the blood type diet, discuss which foods are considered best for type O, and provide some sample meals and diet tips.
The Blood Type Diet
The blood type diet was popularized in the 1990s by Dr. Peter D’Adamo, author of the book “Eat Right 4 Your Type.” The main premise of this diet is that certain foods react biochemically with each person’s blood type in different ways. Therefore, adhering to a specific diet tailored to your blood type can improve health and decrease risk of chronic illnesses like heart disease, diabetes, and cancer.
According to D’Adamo, those with type O blood thrive on a high protein, low carbohydrate diet. Meat, poultry, fish, and vegetables are recommended while grains, dairy, legumes and certain fruits should be limited or avoided. This is because lectins, which are carbohydrate-binding proteins, may interact negatively with type O blood. Here’s a quick overview of the recommended foods for the type O diet:
Recommended
- Meat – especially lean grass-fed varieties like beef, lamb and venison
- Poultry – turkey and chicken
- Fish – salmon, tuna, sardines, cod, etc.
- Vegetables – especially leafy greens and broccoli
- Olive oil
- Fruits – berries, figs, plums
- Nuts and seeds – almonds, walnuts, pumpkin seeds
Avoid
- Grains – wheat, oats, barley, corn, rice
- Beans and legumes – lentils, kidney beans, chickpeas
- Dairy products
- Potatoes
- Bananas
- Oranges
- Cabbage
- Brussels sprouts
But what does the research say about the effectiveness of this blood type diet? Let’s explore some of the key studies next.
Research on the Blood Type Diet
There is limited evidence from scientific studies to support the benefit of following a blood type diet. Here is a summary of some of the key research that has been conducted:
- A 2014 review published in the American Journal of Clinical Nutrition looked at 14 studies on the blood type diet. It concluded there was no reduction in risk for cardiovascular disease, diabetes or cancer among people who followed a diet specific to their blood type.
- Another review from 2013 published in PLoS One found no evidence blood type diets offer any benefits for health conditions like heart disease or diabetes. The authors noted the lack of high quality clinical trials on the blood type diet.
- A study in the journal Blood Cells, Molecules, and Diseases had people with blood type A or O follow their respective diets for 4 weeks. No significant differences were seen in weight loss, body mass index, blood pressure or other health markers between the two diet groups.
- Some proponents of the blood type diet point to its origins matching the optimal diets of prehistoric ancestors thousands of years ago. However, a study in Molecular Biology and Evolution concluded modern humans evolved to adapt to eating a wide variety of diets rather than specialized based on blood type.
Based on the current research, there is not strong evidence that adhering to a blood type O diet provides specific health benefits or reduces disease risk. More robust clinical trials are needed to determine the effectiveness of this diet. However, eating the recommended foods for type O can still be healthy since it emphasizes lean protein, produce and heart-healthy fats.
Best Foods for Blood Type O
While the blood type diet as a whole lacks proven effectiveness, incorporating some of the recommended foods for type O can be beneficial as part of an overall balanced diet. Here are some of the best foods to emphasize if you have type O blood:
Lean Meat and Poultry
Eating plenty of high quality protein foods like meat and poultry aligns with the type O focus on eating lots of protein. Stick to leaner cuts of beef, pork and lamb. Choose skinless chicken or turkey and avoid fried or breaded preparation methods. Grass-fed varieties are preferable when you can find them. Meat provides important nutrients like iron, zinc, and B12.
Fish and Seafood
Aim to eat fish 2-3 times per week, prioritizing fatty fish like salmon, mackerel and sardines that are rich in omega-3 fatty acids. Shellfish like shrimp and clams are also great for type O. If buying canned fish, choose versions packaged in water rather than oil. Beyond their health perks, seafood provides beneficial type O nutrients like iodine, vitamin D and selenium.
Vegetables
Fill half your plate with nutrient-packed vegetables at meals. Focus especially on leafy greens like spinach, kale and lettuce as well as broccoli, asparagus, artichokes, onions and garlic. The wider the variety of veggies you eat, the more antioxidants, vitamins and minerals you’ll get. Roast veggies in olive oil for a flavorful side dish.
Certain Fruits
While oranges, bananas and melons are limited on the type O diet, some fruits are still good to eat in moderation. The best fruits for type O blood include berries, cherries, plums, prunes, figs and olives. Eat fruit as a snack or dessert rather than a main component of meals to align with type O’s lower carb focus.
Nuts, Seeds and Oils
Healthy fats should be part of a type O diet. Cold-pressed olive oil and coconut oil are best for cooking. Snack on nuts like almonds, walnuts and pecans or nut butters. Chia, flax and pumpkin seeds also make great crunchy, nutrient-packed additions to meals and snacks. These provide key minerals as well as soluble fiber.
Herbs, Spices and Condiments
Use liberal amounts of fresh or dried herbs, spices, vinegars and mustards to add flavor to type O dishes instead of relying on salt, sugar or high calorie condiments. Options like garlic, thyme, rosemary, turmeric, apple cider vinegar, mustard and hot sauce jazz up foods without added calories.
Now let’s look at some sample meals that incorporate the best foods for blood type O.
Sample Meal Plan for Blood Type O
Here is a one day sample meal plan featuring optimal food choices for someone with type O blood:
Breakfast
- Turkey bacon, egg white omelet with spinach and mushrooms
- Sliced tomatoes
- Berries
Lunch
- Greek salad with romaine lettuce, cucumbers, red onions, cherry tomatoes, chickpeas, feta cheese and lemon vinaigrette
- Plums
Dinner
- Roasted salmon with garlic and rosemary
- Asparagus sautéed in olive oil
- Quinoa pilaf
- Salad with mixed greens, walnuts and balsamic vinaigrette
Snacks
- Sliced turkey rolled around veggie sticks
- Berry smoothie with almond milk, spinach and protein powder
- Hard boiled eggs
- Edamame hummus with veggie sticks
This provides a good mix of lean protein, produce and healthy fats. Dessert could be fresh fruit salad, roasted figs or dark chocolate. Be sure to stay hydrated by drinking plenty of water throughout the day as well.
Tips for Following the Type O Diet
If you want to give the blood type O diet a try, keep these tips in mind:
- Focus on food quality. Choose grass-fed meats, wild caught fish and organic produce when possible.
- Read labels. Watch out for hidden ingredients like corn, wheat, beans or soy that should be avoided.
- Modify appropriately. Adjust the diet based on your individual health needs and any conditions like diabetes or food sensitivities.
- Supplement mindfully. Speak with your doctor before taking supplements like probiotics or digestive enzymes.
- Stay active. Include regular exercise as part of your healthy type O lifestyle.
- Don’t forget hydration. Drink water throughout the day and limit sugary beverages.
- Allow occasional treats. Depriving yourself can backfire. Enjoy foods not on the type O list in moderation.
- Seek advice. Consult a registered dietitian or doctor if you have any concerns about major dietary changes.
The bottom line is balance. While blood type O has specific recommendations, ditching entire food groups long-term may increase risk for nutritional deficiencies. Monitor how you feel eating certain foods and adjust accordingly rather than sticking rigidly to restrictions.
Should You Try the Blood Type O Diet?
The available research does not confirm significant benefits from following a blood type O diet. However, incorporating the recommended foods can still be healthy as they provide lean protein, antioxidants, fiber and important nutrients. Focus on an overall balanced eating pattern full of minimally processed, nutrient-dense foods. Don’t avoid foods simply due to blood type rather than your individual tolerances.
Certain individuals like endurance athletes, those with food intolerances or people interested in ancestral eating patterns may want to try customizing their diet based on blood type recommendations. Work with a healthcare practitioner to ensure you meet nutrient needs. Listen to your body’s response. Modify the diet and seek personalized advice if needed.
While the effectiveness of blood type diets is debatable, one thing is clear – eating plenty of vegetables, high quality proteins and healthy fats as emphasized in the type O diet can benefit anyone’s health no matter their blood type. Using blood type as a general guide while focusing on whole, nutritious foods may be helpful for some people.
The Bottom Line
The blood type diet recommends specific foods to eat and avoid based on your blood type to optimize health and decrease disease risk. While the evidence for this diet’s effectiveness is limited, eating the foods promoted for those with blood type O can still be nutritious as it emphasizes lean protein, produce and healthy fats. Focus on an overall balanced diet full of minimally processed foods. Consider your individual needs and tolerances first rather than basing decisions solely on blood type. Talk to your doctor to determine if a modified type O diet aligns with your health goals.