I have not heard of a three day diet plan ever before! Are you referring to the three day detox plan? I don't think that there are any specific menus that are involved in such a plan and I am pretty sure that all you need to do is eat healthy and drink plenty of water. Avoid any foods that high on cholesterol during this period and try not to eat too much meat. Veggies and fruits are the best bet during a three day detox plan. Fruit juices are also a good option and you will get the required energy from them.