In recent decades, the vegetarian diet has gained significant popularity, mainly because of its health and environmental benefits. Plant-based vegetarian diets are known to reduce the risk of cardiovascular disease and diabetes by lowering blood cholesterol and improving insulin sensitivity.
Plant-based foods contain higher amounts of fibers, vitamins, minerals, and bioactive compounds, as well as lower amounts of total and saturated fats, as compared to animal-based foods. Despite these health benefits, some vegetarian diets that exclude all types of animal products, such as a vegan diet, may cause vitamin B12 deficiency, as animal food products are the only natural source of this essential micronutrient.
https://www.news-medical.net/news/20231126/Large-scale-study-finds-no-mortality-benefit-from-vegetarian-diets-in-US-adults-challenges-previous-beliefs.aspx