The idea that a person’s ideal diet is determined by his blood type was presented in the late 1990s in the work of naturopathic physician Peter D’Adamo. According to this program, people with blood type O should avoid eating grains. Although the Blood Type Diet remains popular, there is no scientific basis for this approach. Your doctor or nutritionist can help you develop a diet plan specific to your needs and goals.
Blood Type O
According to the blood type diet theory, blood type O was the first blood type. The program characterizes type Os as smart, energetic and powerful -- born leaders with quick tempers. Because the genetic ancestors of today’s type Os were hunters who ate a diet rich in meats and fats and no cultivated grains, the system argues that grains will cause weight gain, gastrointestinal upset and disease in modern-day type Os. There is no scientific support for this hypothesis.
Whole and Refined Grains
Whatever your blood type, grains, especially whole grains, are an important source of nutrients and fiber. The 2005 Dietary Guidelines for Americans recommend that healthy adults consume at least three servings of whole grains per day. The U.S. Department of Agriculture suggests that least half of these grains should be whole instead of white, or refined. The bran and germ have been removed from white grains, giving them a lighter texture but stripping their fiber, B vitamins and iron. Whenever possible, choose whole grains over white.
Whole Grains and Disease
Whole grains offer a wide range of micronutrients and phytochemicals. The Linus Pauling Institute has determined that strong support exists for a relationship between a diet high in whole grains and reduced risk of type 2 diabetes and cardiovascular disease. Whole grains have a lower glycemic index than refined grains, and many nutrients in whole grains, such as folate, potassium and magnesium, have been linked to cardiovascular health. A diet without grains will deprive you of these important benefits.
Whole Grains and Weight Control
Whole grains do not interfere with weight loss for most healthy adults. In fact, they may promote it. Whole grains provide dietary fiber, which contributes to intestinal and digestive health. This can help reduce constipation and abdominal bloating. A study in the November 2010 “American Journal of Clinical Nutrition” showed that higher intake of whole grains leads to lower levels of unhealthy abdominal fat. A diet high in refined grains, on the other hand, has been associated with the presence of more abdominal fat. There is no clinical evidence that people with blood type O experience different results.
References
- Eat Right for Your Type: Official Website of Dr. Peter D’Adamo and the Blood Type Diet
- Langone Medical Center; Blood Type Diet: Eat Right for Your Type; Maria Adams; 2011
- U.S. Department of Agriculture; ChooseMyPlate.gov; Food Groups – Grains
- Linus Pauling Institute Micronutrient Information Center; Whole Grains; Jane Higdon; 2005
- “The American Journal of Clinical Nutrition”; Whole- and Refined-Grain Intakes are Differentially Associated With Abdominal Visceral and Subcutaneous Adiposity in Healthy Adults; Nicola McKeown et al.; November 2010
