Religious leaders shouldn't 'fast' to protest.

Religious people should fast to draw closer to Jesus Christ, in union with Christ's own suffering and in union with His love for all people, and each person.

This is why God gave us the ability to fast, a will to strengthen and "give to" various intentions.   

A 'rational will' separates us from the animals. 

I will accept the Cross Father to be in union with Your Will, "not my will but Your will".   This was Jesus's example of how to use the will to suffer for some great good. 

At bottom what they're doing is essentially this:L They're just playing noisy games; "if you don't do this (or stop doing this..)...I will barely get hungry [and maybe loose a few pounds for summer time!]and then we'll take photos of us and then you'll be sorry because we will shame this and that person, and of course Trump too"