You did it to me
Most certainly I tell you, because you did it to one of the least of these my brothers, you did it to me.
The only description Jesus gave of the final judgment contains no doctrine. Nobody is asked what they believed. They are asked whether they fed the hungry, welcomed the stranger, visited the prisoner, and the surprise on both sides is the same: when did we see you? Christ is met in the least, the ones with nothing to offer in return, and he is met there whether or not you recognize him. This makes every act of service a sacrament and every dismissal of a person a small refusal of God. Today's fast is for someone else.
Today's practice
Take what today's meals would have cost, or the hours they would have taken, and give them to someone who cannot repay you. In person, if at all possible.
The fast · a full day
Sunset to sunset: nothing from last night's supper until supper tonight. The meals belong to someone else. Break the fast gently.
By the calendar, today is Day ?.