The O positive diet is a set of eating and exercise recommendations for people who have type O positive blood. The diet was first detailed in Peter J. D'Adamo's 1996 book "Eat Right 4 Your Type: The Individualized Diet Solution to Staying Healthy, Living Longer & Achieving Your Ideal Weight." The book also contains specific instructions for the three other blood groups, A, B and AB. According to D'Adamo, people with type O blood -- both O positive and O negative -- should adopt particular dietary and lifestyle habits because their blood directly links them to their ancestors, prehistoric hunters who ate primarily meat and vegetables and very few grains. While proponents of blood type-based diets say followers will be healthier, leaner and more energetic, health professionals warn that there is no scientific evidence to back up D'Adamo's claims.
Background
D'Adamo, a naturopath who says he has conducted extensive research in genetic history and nutrition, says that it is important for people belonging to the O blood group to eat similarly to the way their hunter predecessors ate because by doing so, they avoid consuming lectin compounds that are incompatible with their blood. Lectins are glycoproteins located in some plant and animal products that can trigger antibody-like cell clumping or precipitation. D'Adamo contends that eating foods that cause this reaction in the blood can significantly increase a type O person's risk of diabetes, thyroid problems, obesity and digestive system disorders. D'Adamo also says that type O individuals are more aggressive than people belonging to other blood groups and need to engage in specific types of exercise to avoid depression, destructive behavior and health problems stemming from excessive anger and stress.
Recommended Protein Sources
In his book, D'Adamo specifies that people with O positive blood should center their daily meals around lean animal proteins. D'Adamo advises that the most beneficial meats for type O people include beef, venison, lamb and mutton. Fish like rainbow trout, red snapper, cod, halibut, swordfish and salmon are also strongly recommended. Health Care Ministry International's blood type diet guidelines detail that type O people can eat chicken, shellfish and plant-based protein sources like almonds occasionally, but no more than one or two servings weekly.
Recommended Fruits and Vegetables
The most highly recommended vegetables for people belonging to the O blood group include beets, potatoes, parsnips, red peppers, turnips, okra, leeks, all types of seaweed, onions and dark leafy green items such as Swiss chard, spinach, kale, collard greens and broccoli. Recommended fruits include plums, cherries, figs and prunes. Other fruits like apples, bananas, grapes and melons are allowed in small amounts weekly.
Food to Avoid
Type O people are advised to strictly avoid all dairy items and egg-containing products. When following Health Care Ministry International's blood type diet, they also should avoid wheat and corn products, most types of beans and legumes and limit their carbohydrate intake to Ezekiel and Essene bread. Additionally, D'Adamo claims that all types of pork products, avocados and high-acid fruits like oranges, strawberries, tangerines and blackberries can disrupt type O digestion.
Expert Insight
David L. Katz, MD, told "The Oprah Magazine" in 2009 that diets like the one recommended for people with type O blood can cause you to become deficient in essential nutrients. Calcium and fiber deficiencies from this diet can increase your risk of conditions like osteoporosis and cardiovascular disease. Additionally, the Mayo Clinic points out that there are no reputable scientific studies that support the idea you will lose weight or experience better health by following a blood type-based diet. Talk to your doctor about the possible health ramifications before starting any form of the Blood Type diet.
References
- Eat Right For Your Type: "What Makes a 'Type O' An Individual?"; Peter D'Adamo
- Diet.com: "Blood Type Diet"
- Diet TV: "The Blood Type Diet - Type O"
- Drugs.com: Lectin
- "The Oprah Magazine": "Do Blood Type-Based Diets Work?"; David L. Katz, MD; April 2009
- Health Care Ministry International: "Blood Type 'O' Diet"
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