Some people who adopted a vegetarian or vegan diet for health, ethical, and/or environmental reasons discover that clean meat from animals humanely raised on pasture is a superior, back-to-nature alternative. Not only is this type of meat more nutritious and in keeping with the type of meat our ancestors ate, but allowing animals to graze and naturally fertilize grass can actually renew soil health and allow us to grow more nutritious food. This alone is a compelling reason to consider eating ethically raised meat. But improved health is probably the number one reason why some vegetarians are deciding to beef up their diets.
Source: From No Meat to Clean Meat | Healthy Eating | Better Nutrition