Sam Young is a Mormon Bishop and he is concerned about the potential risk to children in the Mormon Church when they are interviewed and asked if they masterbate etc. These interviews take place in private. Sam is highlighting the potential for grooming.
He wants to change policy and this stage of his crusade is his hunger strike. The link above is all about this.
I have written a comment about the normality of a fast - I’ve been brief. Perhaps others could put a short educative note, but maybe not to drown out the importance of Sam’s message.