The Health Promotion Program at Columbia University reports that a fruitarian diet can cause deficiencies in calcium, protein, iron, zinc, vitamin D, most B vitamins (especially B-12), and essential fatty acids. Additionally, the Health Promotion Program at Columbia reports that food restrictions in general may lead to hunger, cravings, food obsessions, social disruptions and social isolation.
Lack of protein in fleshy fruit can make the lifestyle difficult to sustain, and can lead to the condition of hypoproteinemia or kwashiorkor. Nuts (if included) are a good source of protein. Due to the lower digestibility of plant proteins, however, the American Dietetic Association (ADA) states "protein needs might be higher than the RDA (when) dietary protein sources are mainly those that are less well digested, such as some cereals and legumes."
Vitamin B12, a bacterial product, is not found in any fruits. According to the U.S. National Institutes of Health "natural food sources of vitamin B12 are limited to foods that come from animals." Like vegans that do not consume B12-fortified foods (certain plant milks and breakfast cereals, for example), fruitarians need to include a B12 supplement in their diet. This may pose a health risk for strict fruitarians, as the B12 in fortified foods and supplements is derived from bacteria, not fruits. It is also contrary to the philosophy that humans are perfectly evolved to live off fruit.
Claims made by fruitarian advocates have led some to classify the diet as a form of outright quackery.Template:Fact Many notable advocates of fruitarianism in the past, including Morris Krok, Johnny Lovewisdom, Walter Siegmeister/Raymond BernardTemplate:Fact, and Viktoras KulvinskasTemplate:Fact did not adhere to a strict fruitarian diet. Some, like Johnny Lovewisdom, switched to other unorthodox lifestyles (including breatharianism and liquitarianism, juices only), while others, like Morris Krok, recommended against the diet once they stopped.
- ↑ Alice!, Health Promotion Program at Columbia University, Health Services at Columbia, August 23, 2002."Go Ask Alice!: Fruitarian teens". Accessed May 20, 2008.
- ↑ “Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets”. Journal of the American Dietetic Association, 2003, 06. Accessed 22 January 2008.
- ↑ Dietary Supplement Fact Sheet: Vitamin B12.
- ↑ Peaches and a Guitar: Morris Krok Passed Away.
- ↑ Tom Billings: dietary bio, Part B.