Celebs and fashionistas love them some raw-food “cleanses,” and even big-name chefs have embraced the possibilities of so-called living cuisine. Strict proponents of the raw food diet (a.k.a. the uncooked vegan diet) eschew all animal products and any plant-based foods that have been heated above about 118 degrees, the temperature that can be achieved by leaving food out in the sun. These “raw foodists” say that the plants’ beneficial enzymes (their “energy” or “life force”) are destroyed by heat, and that raw foods are thus healthier than their cooked counterparts. But as the LA Times reports (registration required), from a nutritional perspective those claims are half-baked at best.

First, there’s the weight-loss thing. Raw plant matter is filling, fiber-rich, and low in calories, so raw diets certainly do help the pounds melt off. To a scary extent, in fact:

In one of the largest studies of long-term raw foodists in Germany, published in the Annals of Nutrition & Metabolism in 1999, 25 percent of women and nearly 15 percent of men were underweight. Among women of childbearing age, 30 percent had disruptions or cessation of their menstrual cycles—likely related to loss of weight and body fat.

Sounds a little eating-disordery, no? And as for the supposed health benefits of those living enzymes:

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.

People on raw diets are also far more likely to be deficient in vitamin B12, a recent study of raw foodists in the Netherlands found. Of course, that’s to be expected with any vegan diet, since B12 is found naturally only in animal foods and a few plants. Apparently some new-schoolers are bucking tradition and adding raw meat, eggs, and dairy to the raw food diet (it’s about time!), which solves the B12 problem and probably also the weight issue. Not sure if there’s any hope for those “live” enzymes, though.

See more articles