How to Eat According to Blood Type for Long-Term Health

"Eating according to blood type" benefits the body by supporting digestion, insulin production, metabolism, and hormonal balance, as well as aiding weight loss. Furthermore, dietary advice differs by blood group: Group A favors vegetarianism; Group B tends to gain weight easily; Group O emphasizes protein; and Group AB combines vegetarianism with carbohydrates.

Currently, there is insufficient evidence to confirm that following blood type diets produces the health effects often claimed. Most research is of low quality, lacking proper comparison groups and using inappropriate health indicators. Sample sizes are too small to provide statistically reliable differences.

However, although blood type diets lack strong evidence to recommend widespread practice, there are still specific benefits and drawbacks for each blood type's recommended diet. Adjustments can be made to promote health based on general principles of healthy eating.

Eating healthily and preventing disease revolves around two key points:

1. Balance means maintaining equilibrium in both energy and food quantity to meet the body's needs—eating enough to avoid nutrient deficiencies, weight loss, or illness, yet not so much as to cause weight gain, obesity, or related illnesses.
2. Moderation refers to controlling food intake so it neither exceeds nor falls short due to taste preferences. One can eat all kinds of food, including sweets, fats, and salty items, as long as portions are reasonable.

Thailand has established healthy eating guidelines called the Nutrition Mandates, offering nine nutritional principles:

1. Eat all five food groups with variety and regularly monitor body weight.
2. Make rice the staple food, occasionally alternating with other starches.
3. Eat plenty of vegetables and regularly consume fruit.
4. Include fish, lean meats, eggs, and legumes routinely.
5. Drink milk appropriate for one's age.
6. Consume fats in moderation.
7. Avoid foods that are excessively sweet or salty.
8. Eat clean, uncontaminated food.
9. Limit or abstain from alcoholic beverages.

Here are the blood type-specific dietary recommendations that may benefit health:

Group A

Follow a vegetarian diet but include fish, eggs, and milk, along with vegetables, fruits, and brown rice.

Benefits: This diet emphasizes fiber-rich foods that provide potassium, calcium, and magnesium, helping control blood pressure, reduce fat, regulate blood sugar, and contains low saturated fat.

Group B  

Prone to weight gain and weaker immunity; focus on foods rich in omega-3 from fish, green leafy vegetables, brown rice, oats, milk, and eggs.

Benefits: Omega-3 helps reduce inflammation and protects heart and vascular health; fiber from vegetables, brown rice, and oats supports digestion, and protein sources from fish, eggs, and milk are high quality.

Group O

Emphasize protein-rich foods including various red meats, fish and seafood, vegetables, and fruits.

Benefits: Provides high-quality protein, vitamins, minerals, and fiber from fruits and vegetables, but calcium intake should be supplemented with milk.

Group AB  

Vegetarian diet combined with carbohydrates, including soy products and tofu, milk, eggs, low-fat yogurt, oats, vegetables, and fruits.

Benefits: Supplies protein with low saturated fat, fiber from fruits and vegetables, but lacks sufficient healthy fatty acids from nuts, seeds, and fish.

All recommended food groups are healthful, but the key to maintaining health is moderation—choosing good foods in amounts that meet the body's needs. The healthy plate concept serves as a guide.

• 30% vegetables,
• 20% fruit, about 6–8 bite-sized pieces per meal,
• 25% protein,
• 25% rice or starchy foods with high fiber content,
• and one glass of water.

Simple healthy eating principles are to reduce sugar, fat, and salt while increasing fruits and vegetables.

1. Grains and starches

Choose to eat

• Alternate rice with other starch foods such as rice noodles, thin rice noodles, taro, and yam.
• Brown rice, whole wheat bread, and whole grains that are unrefined.

Reduce, avoid, or eat occasionally

• Refined white rice and white bread.
• High-sugar drinks like sweetened water, iced coffee, iced tea, fruit smoothies, green tea smoothies, and bubble tea.
• Sweets.
• Snacks and baked goods such as croissants, cakes, and pies.
• Adding sugar to prepared foods including sauces and condiments like chili fish sauce, dipping sauces, seasoning sauces, and ketchup.

2. Meat, dairy, eggs, and legumes

Choose to eat

• Fish from both freshwater and saltwater, and chicken meat.
• Low-fat meats such as chicken breast and lean cuts.
• Low-fat, unsweetened milk.
• All types of legumes.
• Prepare foods by steaming, boiling, stewing, or stir-frying with little oil, such as clear soups, sour curry, or spicy soup.

Reduce, avoid, or eat occasionally

• High-fat meats including those with skin or fat, like chicken skin or pork belly.
• Salt-preserved or processed meats such as fermented fish, salted fish, sour fermented fish, fermented pork sausage, Vietnamese pork sausage, Chinese sausage, hot dogs, ham, and bacon.
• Burnt or smoked grilled meats such as grilled pork skewers, grilled chicken, barbecue, or Korean barbecue.
• Dairy products high in saturated fat such as butter, cheese, and ice cream.
• Milk and dairy products with added sugar like flavored fermented milk or flavored yogurt.
• Salted nuts.

3. Fats and oils

Choose to eat

• Oils rich in healthy fatty acids like rice bran oil, tea seed oil, canola oil, and olive oil.
• Hard-shelled nuts like almonds, cashews, and peanuts.

Reduce, avoid, or eat occasionally

• Oils and fats high in saturated fatty acids from plants and animals such as lard, butter, palm oil, coconut milk, and non-dairy creamers.
• Foods containing trans fats like margarine, shortening used in baked goods such as cakes and pies, and reused frying oils.
• Fast food or convenience foods like pizza and French fries.
• Coconut milk-based sweets like green curry and pumpkin in sweet coconut milk.
• Stir-fried foods with large amounts of oil or deep-fried foods like fried dough sticks, fried bananas, fried chicken, and oyster omelets.

4. Vegetables and fruits

Choose to eat

• Emphasize fresh vegetables and fruits and consume a variety.
• Select vegetables and fruits according to the season.

Reduce, avoid, or eat occasionally

• Very sweet fruits like jackfruit, rambutan, and longan.
• Preserved fruits such as candied fruit, soaked fruit, and dried fruits like raisins and prunes.
• Vegetables coated in batter and fried.
• All types of pickled vegetables and fruits.

Source: Dr. Wanaporn Thongchom, Health Educator, Health Promotion Unit, Faculty of Medicine, Ramathibodi Hospital, Mahidol University.