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Are lentils good for blood type O?

Lentils are an excellent source of plant-based protein and fiber that can fit into many dietary patterns, including the blood type O diet. However, there are some controversies around whether lentils specifically are beneficial for people with type O blood. This article will examine the evidence and guidance around lentils for blood type O.

What is the blood type O diet?

The blood type O diet was popularized by Dr. Peter D’Adamo in his book “Eat Right for Your Type.” The premise of this diet is that your blood type determines how you should eat for optimal health and weight loss.

People with type O blood are advised to follow a high protein, low carbohydrate diet avoiding grains, legumes, and dairy. The logic is that these foods contain lectins that can trigger inflammation and other issues in people with type O blood. On the other hand, lean meats, fruits, and vegetables are encouraged.

Limited evidence for blood type diets

However, there is limited scientific evidence to support the purported benefits of tailoring diets this way. A comprehensive review in the American Journal of Clinical Nutrition found no studies confirming the health benefits of blood type diets over standard healthy eating patterns. More research is still needed on how blood types may impact diet responses.

Are lentils allowed on the type O diet?

Lentils are legumes, a food group that is restricted on the blood type O diet. Other legumes like beans, peanuts, and soybeans are also to be avoided according to D’Adamo.

This is because legumes contain lectins, which are proteins that can bind to the cells lining the digestive tract. It is hypothesized that the lectins in legumes are incompatible with type O blood and could cause agglutination of red blood cells.

However, these lectin concerns are controversial, as most lectins are destroyed with cooking and are unlikely to survive digestion. There are also many other healthy compounds in legumes.

Some flexibility may be okay

Some nutrition experts state that moderate portions of lentils and other legumes can be incorporated into the type O diet, as long as they are prepared properly. Testing your individual tolerance could be beneficial.

Potential benefits of lentils for blood type O

Despite the type O diet recommendations, there are many characteristics of lentils that could benefit people with type O blood:

Plant-based protein

Lentils are an excellent vegetarian source of protein, with about 18 grams per cooked cup. Replacing animal protein with plant protein is encouraged on the type O diet, so lentils could help meet protein needs.

High fiber

With 16 grams of fiber per cooked cup, lentils can help improve gut health and regulate blood sugar levels. A fiber-rich, low glycemic diet is recommended for type O.

Iron and folate

Lentils provide substantial amounts of iron needed for healthy red blood cells. They are also an excellent source of folate, which is important for heart health and preventing neural tube defects in infants.


The polyphenols in lentils act as antioxidants to reduce inflammation in the body. Controlling inflammation is a goal of the type O diet.

Low glycemic index

Despite their carbohydrate content, lentils have a low glycemic index of 29. This means they do not spike blood sugar levels rapidly compared to other high carb foods.

Nutrient Amount Per 1 Cooked Cup
Calories 230
Protein 18g
Fiber 16g
Iron 6.6mg
Folate 358mcg

Potential concerns with lentils for blood type O

Despite their nutritional attributes, there are some potential drawbacks to lentils for those with type O blood:

Lectin content

Lentils do contain lectins like other legumes. Cooking at high temperatures can help reduce lectin content. However, some lectins may remain active.

Digestive effects

The high fiber content of lentils could cause digestive upset in some people with type O blood, who are prone to sluggish digestion. Introducing lentils gradually could help assess tolerance.

Carb content

While the glycemic index is low, a 1 cup serving of lentils still provides about 40g total carbohydrate. This is considered high for the type O diet, which focuses on low glycemic veggies as carbs instead. Moderation would be important.

Blood type diet non-compliance

Strict followers of the type O diet wishing to completely eliminate all legumes would have to avoid lentils as well. However, effects may vary individually.

Tips for incorporating lentils into a blood type O diet

For those who wish to incorporate some lentils into an otherwise type O compliant diet, here are some tips:

– Start with small 1/4 cup servings to assess tolerance

– Try different types – green, brown, red, French, black beluga lentils

– Cook thoroughly to reduce lectins – boil, stew, or pressure cook

– Pair with non-starchy veggies like leafy greens, asparagus, broccoli

– Season with olive oil, garlic, onions, herbs and spices to improve digestion

– Limit higher carb meals with lentils to only 1-2x a week

– Substitute half the lentils in recipes with mushrooms or eggplant for lower carb options

– Experience with lentils very individually, so adjust as needed


The nutritional benefits of lentils suggest they may be reasonably incorporated into a blood type O diet for some people. Their protein, fiber, antioxidants, and low glycemic impact could complement the goals of this dietary pattern.

However, some controversy remains around the lectin content and carb load of lentils for strict type O compliance. Individual experiences seem to vary – some may tolerate lentils well while others notice more digestive upset. Starting slowly and cooking thoroughly can help assess personal tolerance.

In the absence of strong evidence for blood type diets, focusing on an overall healthy eating pattern with lean proteins, produce, and whole foods seems most prudent. Lentils can be a tasty addition in moderation if they agree with you. As with any diet, it is wise to meet regularly with a healthcare provider to help determine the right nutritional plan for your individual needs and health status.