John Calvin wrote, "Holy and lawful fasting has three objectives. We use it either to weaken & subdue the flesh that it might not act wantonly, or that we may be better prepared for prayers & holy meditations, or that it may be a testimony of our self-abasement before God when we wish to confess our guilt before Him."
Hm... "weaken and subdue the flesh that it might not act wantonly".
In his writings, the Apostle Paul ties the sin nature to the body. He affirms again & again that somehow there is a connection. As strange as it sounds, it makes sense. Think about it: When we shed our bodies we also shed our sin nature. They're connected. The Apostle John talks about the lust of the flesh, lust of the eyes & the boastful pride of life as comprising "all that is in the world".
I don't know how that all fits together; but I wonder if there are parallel prescriptions in regard to fasting for those other two arenas of sinfulness. When we deprive our flesh of indulgence, Calvin indicates that our bodies become more inclined to subject themselves to the sacrificial Way to which we're called. Perhaps, if we deprive our eyes & our vanity of similar indulgence, similar training might occur?
Could there be a fasting of the flesh (lust), a fasting of the mind (eyes) & a fasting of the heart (pride). I know, I know... 1 Tim 4:8 says, "bodily discipline is of little profit"; but 1 Tim 4:7 says, "discipline yourself for the purpose of godliness". I s'pose you'll have to work that one out for yourself; but for me, I'm weary of the strong wantonly influences of my body, mind, & heart & am feeling inclined to a bit of self-denial & fasting.