For the medical world, for those who are conscious of their diet, and for those who values their health, fasting is considered because it is known that it gives our body a chance or a time to do its self-healing mechanisms to repair and strengthen damaged organs. It keeps your mucosal lining healthy. It is considered as a good therapeutic act that helps us recover from illness and bad health conditions. And a lot more reasons to count. But the most important reason that I wish to underline here is that fasting keeps your body less intoxicated, detoxified or at least prevents you from acquiring more toxins. In other words it takes you back to the original composition of your body.
The practice of fasting is not only found in religions like what you know. Great philosophers like Plato and Socrates had been doing it and recommended as part of a healthy life. But because we live in a society where religion is evident and part of it, I would not be surprised if the fasting that you know is more of a spiritual act. So I feel obliged here to site a few words regarding that. Before fasting became part of the Christian and Islamic traditions, the Jewish religion - roots of these two monotheistic religions, had been long practicing it already. Fasting is done when a famine prevails, a torture is received, a misfortune is in the frontier, a sin is committed, if God "turns away his face on them", etc. Alongside with this act of fasting is that putting sackcloth and spreading of ashes. All three indicates of going back to the original identity of man before God.
Fasting had been also part of demonstrating a cause or a protest. We have the famous example of Gandhi in the past. And to not give you a long list, I'll set as an example here Yndira Sandoval of Mexico, a young Mexican politician who started yesterday hundred hours of fasting in memory of the women victims, assassinated in her country as well as to fight for the recognition of femicide in the 32 states of Mexico. Fasting is used to protest the recognition of natural rights of human beings. It is used to demonstrate one's personal claims either for himself/herself or for others.
I have brought all these aspects out so that you will not just simply complain about fasting and will say that its a "church" thing. Second, because some would intend to convert or divert fasting into something else - social work, other activities that can bee seen, stopping vices, saving money, etc.
I would dare say that fasting is not an act towards others, it's a personal thing that helps you become more available for others later.
It is not about discharging energy, it's about conserving.
It is not about change or conversion, it's more about giving a chance for your body or yourself to change and go back to the original composition of your being.
It is not about working or proclaiming something, IT IS SIMPLY NOT EATING.
It is not about helping others as others would think that solidarity could substitute fasting, it is more of CLEANSING ONESELF and becoming not only pure in body but also of our own intentions.
It is not about solidarity, its about self-discipline.
Aside from fasting, act. And do not "act" in order to escape from not eating.
And speaking in spiritual tone, fast so that when you go through life surgeries, it would be easier for you to be healed and spiritually clean.
Fast! You will not die if you won't eat a single meal a day this season of lent. Besides its just for 46 days. If you are not bound by the canon law, at least consider it as a health care. Be cleansed! Who knows you might not just be simply spiritually intoxicated but also physically intoxicated.