It is a very common mistake to think that veganism is a healthy and sustainable diet, so would the vegetarian diet. Whether we want to or not, the human being is biologically an omnivore, that is, in order to take advantage of the nutrients of a purely vegetable diet, he should have a much longer intestine than he has. It therefore needs the ingestion of a certain amount of animal proteins for these provide the necessary vitamins and trace elements that are not available in vegetables, or replace them with food supplements (yeasts or others), but more natural with animal products such as dairy and eggs. Even our closest relatives like chimpanzees and bonobos supplement their diet with insects and other animals. What is not sustainable or healthy is our current diet, which includes meat and animal products, not 2-3 times a week, but 3 times a day / 7 days a week. This is the real problem, caused by massive livestock and overfishing, with all its negative effects on the environment, apart from the consequences on our health (obesity, coronary diseases, diabetes, rheumatic diseases, allergies, etc.)