Today’s Gospel reading of the poor woman who places two mites in the temple offering is a good reminder for us as we approach Great Lent.
The passage states:
And He looked up and saw the rich putting their gifts into the treasury, and He saw also a certain poor widow putting in two mites. So He said, “Truly I say to you that this poor widow has put in more than all; for all these out of their abundance have put in offerings for God, but she out of her poverty put in all the livelihood that she had.” (Luke 21:1-5, NKJV)
There are those who are healthy and able to approach the Great Fast (Lent) with strictness in their ascetic endeavors; they should do so to the degree that their spiritual father has allowed. They are like the rich men who poured out their offering unto the Lord; it is pleasing in His sight. The Lord has given them much, so much will be expected of them.
There are others, however, who struggle with their health and find that anything other than very light fasting can damage their already fragile condition. Such people should discuss their situation with their spiritual father. If they bear their sickness without complaining, but instead thank God for all things, then whatever tiny ascetical efforts are made will be like the two mites the poor widow placed in the offering. They perhaps have given more than everyone else, though it does not appear that way on the surface.
Saints Barsanuphius and John teach something similar. A fellow desert dwelling monk wrote to them stating he was discouraged because his poor health prevented him from fasting like the others.
St. Barsanuphius replies,
As for fasting, do not grieve. For as I have already told you, God does not require of anyone beyond their ability. What else is fasting but discipline of the body…?
However, illness is greater than discipline, and is reckoned as a substitue for ascetic behavior; and this is even truer of the person who endures it with patience and gives thanks to God. That person reaps the fruit of salvation from such patience…
Give thanks that you have been exempted from the toil of regular behavior. So, if you eat ten times [a day], do not grieve, for you are not condemned. For this is neither a result of demonic action, nor of slack thought; but it is happening to us in order to test and benefit the soul. 
When we have involuntary afflictions, we must try to endure these with patience, humility, and thanksgiving. Doing so is the ascetic endeavor that God has given us; many times it is one that will extend well beyond the Fast, when others are able to relax a bit. God sees our struggle and has allowed this hardship for our salvation.
For people who are struggling with their health, there may be other things that can be done during the Great Fast: giving up social media, increasing the amount of prayer time each day, working through additional spiritual reading, and for all people: moderation in eating at every meal. Regardless, speak with your spiritual father about a “game plan” for Great Lent.
For those who are healthy: run the race of the fast with love and perseverence, not paying attention to the fasting of others around you. For those with health complications: whatever efforts you make, do so with love and patience, enduring the involuntary hardships without complaining. God will see your efforts and reward you for your twopence offering.
 Barsanuphius and John, Letters from the Desert, translated by John Chryssavgis, St. Vladimir’s Seminary Press, 2003. Pages 80-81.
The featured image is an icon from the Museum of Dionisy’s Frescoes featuring the widow who gave the two mites and the healing of the blind men. It is from www.dionisy.com