The belief in the benefits of raw foods—sometimes called “living foods”—is nothing new. Sylvester Graham, for whom the cracker is named, promoted raw foods 150 years ago, just as some chefs, cookbooks, celebrities and Web sites promote them today. Among other claims, raw food diets are said to eliminate headaches and allergies, improve memory and immunity, ease arthritis, and reverse diabetes. Proponents say that cooking destroys nutrients, enzymes and the “life force” of the food itself.

The basics. A raw food diet is based mostly or exclusively on uncooked and unprocessed plant foods (often organic), including fruits, vegetables, nuts, seeds and sprouted grains. Most followers are strict vegetarians, though some eat unpasteurized dairy foods and sometimes even raw eggs, meat and fish. Foods are prepared using blenders, processors and dehydrators, and can be served either cold or warm, but not hot enough to cook them. Truly dedicated raw foodists shun refined sugar, vinegar, coffee, tea, soy products, most vegetable oils, dried herbs and alcohol.

The benefits. Raw food diets encourage people to eat lots of fresh produce and other nutritious foods that are low in saturated fat, cholesterol and sodium, and high in fiber. Few studies have compared the health effects of a raw food diet versus other eating patterns, but vegetarians, in general, tend to have a lower risk of heart disease and are less likely to be overweight. And in a study from Roswell Park Cancer Institute in Buffalo, people who ate the most raw (as compared to cooked) cruciferous vegetables had a reduced risk of bladder cancer, possibly because the raw vegetables retain more cancer-protective isothiocyanates. Cooking, after all, does reduce some phytochemicals, including isothiocyanates, as well as many vitamins.

The drawbacks. Some nutrients and potentially beneficial plant compounds are less available to the body in the raw state. Heat is needed to break down a plant’s cell walls and release the compounds. Cooking a carrot releases extra beta carotene, while cooking tomatoes releases more lycopene.

Of more concern, some uncooked and unpasteurized foods pose a risk of food poisoning, which is especially dangerous for pregnant women, young children, the elderly, people with compromised immunity and those with chronic medical conditions, such as liver or kidney disease. Raw sprouts, raw oysters and raw (unpasteurized) milk products have been the cause of many outbreaks of foodborne illness in recent years. Heat kills pathogens. Depending on how strict the diet is, people on raw food diets may also need to take supplements to make up for potential shortfalls in calcium, iron, zinc, vitamin B12 and other nutrients.

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