Kathy Freston, the author who promotes a vegan diet, appeared on the Oprah Winfrey show on Tuesday as the program highlighted a one week trial by the majority of the show's staff to try the diet.

A vegan diet involves eating nothing that comes from an animal such as meat, fish, milk or eggs.

Vegan-friendly meals can include vegan cheese, meat substitute sauce, vegetables and whole grains.

Freston said on the program that she obtains protein from legumes and whole grains, eating food such as black bean burritos, lentil soups and vegan chilli.

Vegan snacks presented on the program included Daiya, which is used as a cheese substitute made primarily from tapioca and arrow root flours and pea protein. Also featured on the show's website was Pumpernickel bread, and a smoothie made from blueberries, banana, non-dairy milk and frozen broccoli.

Another type of food which the staff ate was meatless meat burgers, which are typically made from textured soy protein.

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