One type of diet that is increasingly popular is the vegetarian diet. It is estimated that in the United States there is a 5% of the population declaring vegetarian and 2% vegan declared, which also excludes all animal products such as eggs or milk. Dietary factors account for at least 30% of all cancers in Western countries. An study examined the association between dietary patterns (non-vegetarians, lacto, pesco, vegan, and semi-vegetarian) and the overall cancer incidence among 69,120 participants. It found that the vegan diet protects against cancer development .
Depending on what the exact type of diet is has been found that it can also protect against obesity and type II diabetes. In one study  with 22,000 men and about 39,000 women, body mass indices were obtained according to the kind of diet so that the lowest were vegans 23.6 kg / m2, followed by lacto-ovo vegetarians 25.7 kg / m2, piscivegetarianos, 26.3 kg / m2, semivegetarians 27.3 kg / m2 and no vegetarian 28.8 kg / m2. The incidence of type II diabetes was also measured being the lowest rate in vegans 2.9% and the higher in non-vegetarians with 7.6% . The indices of the other groups were intermediate of these two in the same order as above. It seems therefore vegetarian and vegan diet is protective against obesity, cancer, cardiovascular risk and type II diabetes.
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 VEGETARIAN DIETS AND THE INCIDENCE OF CANCER IN A LOW-RISK POPULATION. Yessenia Tantamango-Bartley,1 Karen Jaceldo-Siegl,1,2 Jing Fan,1 and Gary Fraser1
 Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes. Serena Tonstad, MD, PHD,1 Terry Butler, DRPH,2 Ru Yan, MSC,3 and Gary E. Fraser, MD, PHD4