As a rule I think breaking the fast on freshly juiced organic oranges is the norm, but almost any fruit can be used........to quote from Dr H M Sheltons Hygienic System Vol III on breaking the fast..........
"The care that must be exercised in breaking a fast is in proportion to the length of the fast and to the general condition of the fasting individual. The approved plan is to break the fast on liquid food, using for this purpose fruit juice, or tomato juice, or Watermelon juice, or vegetable broths. Fruit juice--usually orange juice--is used most often.
Orange juice, grapefruit juice, or fresh tomato juice are excellent with which to break a fast. Watermelon juice or the juice of the fresh pineapple or of fresh grapes may also be used. A half a glass may be given at the start. After an hour, another half glass may be given. Juice may be given every hour the first day. The second day a whole glass of juice every two hours may be employed. On the third and fourth days give the whole orange or grapefruit and on the fifth day other foods may be added. Large meals should not be attempted in less than a week. These instructions are for the long fast. A short fast requires less care in breaking and is usually followed for several days by an eliminating diet.
There is a tendency on the part of the faster to overeat, not alone because he is hungry, but also because he is desirous of regaining his weight. His friends also urge him to eat. Upton Sinclair truly says: "A person at the end of a (long) fast is an agitating sight to his neighbors, and their one impulse is to get a 'square meal' into him as quickly as possible."
Upton Sinclair eventually denounced Veganism because it did not give him the physical/mental energy to do what he wanted. As posted by Naturalist.
I personally do not agree with Veganism either.
Red meat has been linked to cancer, so my own choice is Coldwater fish and Organically reared chicken.