I went on an elemental diet for two weeks to give my stomach a break from digestion - I used Vivonex. You could use it as a meal replacement. BUT it is expensive and completely vile. You definitely have to mix it with a crystal light package or something (I used Hansen's Natural Fruit Stix packets - Pink Lemonade). Occasionally I will still drink a Vivonex when I feel like I can not handle a meal but I am hungry. They are REALLY gross though!