Raw foodists show B12 deficiencies in studies.

No exact definition exists, but raw food diets are often described as "uncooked vegan diets" -- which exclude all animal products and byproducts -- or more loosely as "uncooked vegetable diets" or "living foods" diets. Adherents consume from half to virtually all of their foods raw. Aside from fruits and vegetables, the diets include raw nuts and seeds and are rounded out with sprouted grains and beans.

Those who aim to consume "living foods" do their best to eat foods as quickly as possible after harvest. Devotees say that beneficial components in plants -- variously referred to as enzymes, energy or even a life force -- are destroyed when foods are heated above a temperature of about 118 degrees.

The number of raw foodists in the U.S. is unknown, and very little research exists documenting their eating habits. They cited health as the primary driver in adopting the diet as well as a number of perceived advantages, including disease prevention, faster healing, weight control, better digestion, more energy and a greater connection with nature.

Research has yet to prove whether raw food can provide all of these benefits, but the diets have some potential shortcomings.

A raw vegan food plan may lack adequate protein and calcium and is likely to be deficient in vitamin B12. A compound found naturally only in animal foods, vitamin B12 protects nerve fibers and genetic material. In a recent study of 201 raw foodists in the Netherlands, published in the Journal of Nutrition, 38% were vitamin B12 deficient, and more than half had elevated blood levels of homocysteine, an amino acid that requires vitamin B12 for processing and that, when elevated, increases heart disease risk.

A diet rich in raw plant matter is bulky, filling and low in calories, so it is not surprising that the adoption of a living foods diet is associated with a substantial loss of weight. In one of the largest studies of long-term raw foodists in Germany, published in the Annals of Nutrition & Metabolism in 1999, 25% of women and nearly 15% of men were underweight. Among women of childbearing age, 30% had disruptions or cessation of their menstrual cycles -- likely related to loss of weight and body fat.

It should be noted that the plant enzymes that raw foodists attempt to preserve are no match for the highly acidic environment of the stomach. There, they're rendered inactive before digestion is complete. And some phytonutrients, such as the brightly colored carotenoids found in tomatoes, spinach and carrots, are not as readily absorbed from raw foods as they are from cooked foods. Similarly, the magnesium, calcium, iron and zinc naturally present in whole grains are released more thoroughly during cooking.

Anthropologists Richard Wrangham and Nancy Lou Conklin-Brittain of Harvard University say humans were meant to consume cooked foods. Heating foods renders them more digestible -- allowing better absorption of much-needed calories.

They point out that humans have cooked foods for more than 250,000 years, a time period long enough to produce biological adaptations -- smaller teeth, longer small intestines and smaller colons than our ancestors -- in response to eating a cooked-food diet.

Courtesy of LA Times

Bonnie - it is refreshing to see someone besides myself bring this information to light. I have said for a long time that humans, especially with certain genetic variations, do not thrive on raw/vegan diets for the reasons mentioned above. I have seen clients who have followed these diets, had major downturns in their health, and took several years to build it back. Going back to my core philosophy, balance is key. Make sure your food is real, minimally processed, and preferably organic, creates the best of both worlds!