The belief in the benefits of raw foods is not new. Sylvester Graham, for whom the cracker is named, promoted raw foods 150 years ago, just as some chefs, cookbooks, celebrities and websites 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.
Raw food diet basics. A raw food diet is based mostly or exclusively on uncooked and unprocessed plant foods, 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.
Raw food diet 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 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, people who ate the most raw cruciferous vegetables had a reduced risk of bladder cancer, possibly because the raw vegetables retain more cancer-protective substances.
Raw food diet 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 milk products have been the cause of many outbreaks of food-borne 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.
The enzyme argument. Raw foodists claim that enzymes in raw foods aid digestion, prevent “toxicity” in the body and have other curative effects. But these enzymes are there for the plants, not us. Moreover, they are largely inactivated by the highly acidic environment of the stomach and thus cannot aid digestion farther down in the intestines or have other benefits. And there’s no evidence that the enzymes can become reactivated in the intestines, as some raw foodists say. In any case, even if some enzymes do survive, the body usually makes all the enzymes it needs to digest and absorb food.
A matter of balance
Raw fruits, vegetables, nuts and seeds are certainly good for you. But you don’t need to—and should not—restrict yourself to raw foods only. There’s no conclusive evidence that a pure raw food diet will prevent or cure any condition or disease. Plus, it’s an extreme diet that’s hard to maintain over the long run, deprives you of some of the tastiest and most nutritious foods, makes dining out difficult, and can be deficient in some nutrients.