What is the actual point of fasting from food?

This is what the Holy Fathers talk about: that in the pre-fallen world the immortal soul ruled over the body, the spiritual ruled over the physical. But then in our fallenness the body begins to rule over the soul. We want to do something good and righteous, but what happens? We get tired. Or we want to fast, but we end up falling into the temptation of eating foods that we shouldn't be eating. And in this way the gluttony, the belly, the desires of the flesh, end up ruling over our soul, over what is more noble, over what we should be taking care of. In fact, this is why we enter upon these periods of fasting, because the Holy Fathers tell us that during these periods of fasting what is upside down, meaning that the body is ruling over the soul, becomes right side up. The soul begins to take back control of the body and says, no, we're not going to eat whatever it is that you want, whatever it is that you crave. And even if you get tired, and even if you feel lethargic, I'm not giving in to you. I'm not going to feed you. You are not my master. The soul is the master of the body.