Raw food diets also have positives and negatives.

A similar study, also conducted in Germany, examined 201 participants who consumed at least 70 percent of their total food intake as raw food and who had followed this diet for at least two years. The majority of subjects ate small amounts of raw meat and fish, while approximately 20 percent were lacto-ovo vegetarians and 20 percent were vegan. More than three-quarters of the subjects ate more than 90 percent of their food in raw form. The diets of the subjects were quite low in protein with an average protein intake of 30-40 grams per day. Current recommendations call for 56 grams of protein for men and 46 grams for women. Dietary fat was around 30 percent of calories, and intakes of saturated fat were low. Blood cholesterol and LDL cholesterol concentrations were low. On the other hand, HDL (good) cholesterol concentrations were also low, with the lowest levels seen in subjects eating the greatest amounts of raw food. Close to 40 percent of participants had vitamin [B.sub.12] deficiency, and 50 percent had elevated homocysteine concentrations, which can be caused by a vitamin [B.sub.12] deficiency and has been associated with an increased risk of heart disease. Subjects who regularly used vitamin [B.sub.12] supplements had higher vitamin [B.sub.12] and lower homocysteine concentrations than subjects who did not use supplements. The low concentrations of HDL cholesterol and elevated homocysteine concentrations seen in this group following a raw food diet raise concerns about an increased risk of heart disease and stroke. It is clearly important for those following raw food diets to have adequate and reliable sources of vitamin [B.sub.12].

Koebnick C, Garcia AL, Dagnelie PC, et al. 2005. Long-term consumption of a raw food diet is associated with favorable serum LDL cholesterol and triglyceride but also with elevated homocysteine and low serum HDL cholesterol in humans. J Nutr 135:2372-78.