Many researchers come the same answer that vegetarianism helps fight against cancer* (For fish-eating vegetarians, the protective link was even stronger). A vegetarian diet, especially one that includes fish, significantly reduces the speed of cancer.
However, the same researchers say that vegetarianism is not good for a healthy body. There is also research* showing that vegetarians are just more concerned about health than the general population of the Earth.
But even if you are completely healthy not necessary to overeat meat, all good in the middle. because an animal protein may significantly increase the risk of premature mortality from all causes*, among them cardiovascular disease , cancer and Type 2 diabetes. Heavy consumption of saturated fat and trans fats may double the risk of developing Alzheimer's disease*. Low-carb, high-animal-protein diets promote heart disease* via mechanisms other than just their effects on cholesterol levels. When fat calories were carefully controlled, patients lost 67 percent more body fat than when carbohydrates were controlled. An optimal diet for preventing disease is a whole-foods (whole grains foodhole grains food*), plant-based diet that is naturally low in animal protein, harmful fats and refined carbohydrates. Besides, vegetable fats are not deposited in the body fat. This is due to their chemical structure and physical properties (presence of unsaturated chemical bonds). Substances with a large number of unsaturated bonds are not typical for a human body and are involved in fast metabolism as an energy source. Another reason to think for meat lovers: The World Health Organization (WHO) declared* 26.10.2015 that red meat falls into the category of compounds that are “probably carcinogenic to humans,” Group 2A, while processed meats fall into the graver Group 1, compounds that are “carcinogenic to humans,” along with cigarette smoke and asbestos. It doesn’t mean meat is as bad for you as smoking, just that there’s enough evidence now to put in this category. Also worth considering ways of processing meat in different countries.
During one of the study* was established that a vegan diet might help people with diabetes. However, it turned out that the achievements are not associated with a vegetarian diet, but simply with diet. Just a vegetarian diet is stricter and cleans the body well. Another study (1 *), (2 *) says that the diet with high vegetables, fruits, legumes, cereals/grains, fish, and healthy monounsaturated fats like olive oil. And a low intake of unhealthy fats, like saturated fats, dairy, meat, and poultry; and mild to moderate amounts of alcohol (red wine is a common element of the diet), “promotes you get against brain atrophy [shrinkage]," (all about how to keep the brain*) said study author Yian Gu, an assistant professor of neuropsychology at Columbia University in New York City. In fact, the modern fast food and vegetarianism - the two extremes side, but really health diet - somewhere in between. In the same time the problem of vegetarianism and veganism, that instead of meat there uses ultra-processed foods, it is really even more harmful for the body than whole meat.
Yet, the human body is not adapted to veganism (complete rejection of animal fats, including milk and fish). The main natural source of B12 for human remains animal food, including meat, milk and eggs. Also, rich sources of essential micronutrients is fish and seafood.
For example: 03/17/2015, page D6 NewYork “Diet May Cut Colon Cancer Risk.”, «Vegetarianism. Riddles and lessons, benefits and harms "(SPB . : All, 1999), nytimes
Quotes from the Thomas Campbell's book. «The China Study Solution: The Simple Way to Lose Weight and Reverse Illness.»
"... people which ate more animal products have higher levels of cholesterol, which in turn is associated with an increased incidence of several types of cancer, diabetes and other diseases prevalent in rich countries." (Campbell T. C., Junshi C. Diet and chronic degenerative diseases: Perspectives from China // American Journal of Clinical Nutrition, 1994. Vol. 59. Pp. 1153S–1161S)
"... people which consuming more animal food, are more common heart disease, but in many traditionally" vegetable "cultures around the world heart disease has historically been a very rare cause of premature death." (Scrimgeour E. M., McCall M. G., Smith D. E., Masarei J. R. Levels of serum cholesterol, triglyceride, HDL-cholesterol, apoproteins A-I and B, and plasma glucose, and prevalence of diastolic hypertension and cigarette smoking in Papua New Guinea highlanders // Pathology, 1989. Vol. 21. Pp. 46–50.), (Campbell T. C., Parpia B., Chen J. Diet, lifestyle, and the etiology of coronary artery disease: The Cornell China study // American Journal of Cardiology, 1998. Vol. 82. Pp. 18T–21T.), (Ornish D., Scherwitz L. W., Billings J. H. et al. Intensive lifestyle changes for reversal of coronary heart disease // The Journal of the American Medical Association, 1998. Vol. 280. Pp. 2001–2007.), (Himsworth H. Diet and the incidence of diabetes mellitus // Clinical Science, 1935. Vol. 2. Pp. 117–148.)
"Scientists have repeatedly shown that vegetarians and vegans on average, slimmer than their meat-loving cousins." (Fraser G. E. Vegetarian diets: What do we know of their effects on common chronic diseases? // American Journal of Clinical Nutrition, 2009. Vol. 89. Pp. 1607S–1612S.), (Newby P. K., Tucker K. L., Wolk A. Risk of overweight and obesity among semivegetarian, lactovegetarian, and vegan women // American Journal of Clinical Nutrition, 2005. Vol. 81. Pp. 1267–1274.), (Dwyer J. T. Health aspects of vegetarian diets // American Journal of Clinical Nutrition, 1988. Vol. 48. Pp. 712–738.)