Are vegetarian diets healthier than meat-based diets?

Vegetarian diets vary greatly and can range from avoiding meat through to a strict vegan diet, where all foods of animal origin are excluded. Some studies show that vegetarians suffer less from heart disease, some cancers, high blood pressure and type 2 diabetes, and that they live longer than meat-eaters. However, any beneficial effect is also likely to be due, in part, to a generally healthier lifestyle adopted by vegetarians including not smoking and taking more exercise(3). It is not simply a case of omitting meat from the diet. Thus, a vegetarian diet is not automatically healthier than an omni-vorous diet and non-vegetarians who are health conscious can live just as long as vegetarians. Vegetarian diets can even be unhealthy if meat and animal products, rich in essential vitamins (e.g. vit B12) and minerals (e.g. iron, zinc), are not substituted by nutritionally appropriate foods or compensated by adequate food supplements.