I would like to know, what is exactly a Daniel fast? when it is appropriate to do and how to do it?
Thank you for your reply
As far as I know, classical Jewish sources do not place value on, or even refer to the 'Daniel fast', as a discrete regimen. Indeed, Daniel's diet seems to have been the result of his problem with the particular food he was served:
But Daniel purposed in his heart that he would not defile himself with the king's food, nor with the wine which he drank; therefore he requested of the chief of the officers that he might not defile himself (Daniel 1:8).
The issue is generally understood to have been that the food he was served was not kosher (cf. Ibn Ezra to Daniel 1:8).
The fast seems mostly popular among Christians (e.g.), and involves certain dietary restrictions primarily those which are always binding on Jews anyway, (although there are different versions of the practice).