Toxins can lead to infections on the inner surface of the large intestine. The antioxidants from vegetables can cleanse the colon and reduce the risk of cancer. Vegan diets that include veggies, fruits, and whole grains have been proven to work faster. There are studies that examined the positive effect of vegan diets on LDL (low-density lipoprotein) cholesterol levels. Vegan diets reduce the ‘bad’ cholesterol level because they don’t contain unhealthy cooking oils.