Nutritional yeast is a deactivated yeast. It comes in a yellow, flake form. Nutritional yeast has a strong flavor that has been described as nutty or creamy, making it a popular ingredient in cheese substitutes. It is often used by vegans in place of cheese. Directions: Take 2 tablespoons daily mixed into milk, fruit juice, or vegetable juice. It can also be used in vegetarian recipes or added to protein shakes to increase the nutritional content.