Vilang is quite right and just to clarify his position here.
It was always the tradition for decades to break the fast of any length with juice, and in particular with the juices of the Orange and/or apple.
This was the recommendation and general practice, because most fasters did not experience the return of hunger due to financial or time-constraints in healing their diseases/illnesses. Liquid food was found to be the most digestible and nourishing in re-nurturing their limited digestive capacity for those who had not experienced the return of hunger.
For those who did undergo a complete fast, or a "finish-fast" and where genuine hunger had returned, then solid raw food of a high-water-content (mainly fruit) was considered to be the ideal, as the body would be fully receptive for food and handle nutrition with ease.
It is inevitable that some people will not tolerate fruit juices in the breaking of a fast, but this was the exception and not the norm', and where the culprit in most cases would be "gulping" the juice instead of sipping and mixing it with saliva (the first step in the digestive process).
In answer to the poster who has said in this thread that OJ is very acidic, this is a fallacy and not to be believed, as once fruit juice of any kind (including acid fruits of orange, grapefruit,etc) are consumed, they become alkaline within the body: this is generally known nutritionally.
I have always broken my own fasts with freshly squeezed OJ and in particular after my two extended fasts with only distinct benefit, as have thousands upon thousands of others.