Question: Wouldn't it be more sacrificial for someone to give up foods that they really loved such as candy rather than meat which they may not care for that much anyhow?
It is the incorrect to think about fasting as only about food and what we should "give up" - as we read in Psalm 50 (or 51 in certain translations), the sacrifice to God is humility. Therefore when we associate fasting only with what type of foods we give up, our actions are no longer a fast but instead we are dieting.
The practice of fasting was passed on to the early Christian Church from Judaism, and indeed we read Christ Himself instruct His followers on how to follow the fast (Matthew 6:16-18). It is important to note that the Lord instructed us to follow His commandment "when you fast", not "if you fast".
The purpose of the fast is to learn discipline, to gain control of those things that are indeed within our control but that we so often allow to control us. And in our Christian faith, we do so in order for us to become Christ-like, to be perfect as the heavenly Father is perfect (Matthew 5:48).
St. John Chrysostom (sometimes remembered as Mar Ivanios in the 5th Thubden) instructed us to think of fasting as a medicine, and the intention is for healing which is the correct understanding of Christian Salvation. But, just as one may become more sick if they take the wrong medicine, same is the case if we pretend to observe the Fast using our own formula and rationalism.
Fasting is obedience, prayer, discipline, Scripture ... as a Church and the Body of Christ, we make a special effort during these times of Lent to be One in Spirit and action. To quote further from St. John Chrysostom's teachings:
"Fasting is the change of every part of our life, because the sacrifice of the fast is not the abstinence but the distancing from sins. Therefore, whoever limits the fast to the deprivation of food, he is the one who, in reality, abhors and ridicules the fast. Are you fasting? Show me your fast with your works. Which works? If you see someone who is poor, show him mercy. If you see an enemy, reconcile with him. If you see a friend who is becoming successful, do not be jealous of him! If you see a beautiful woman on the street, pass her by. In other words, not only should the mouth fast, but the eyes and the legs and the arms and all the other parts of the body should fast as well."
If we do not have the discipline and conviction to joyfully follow the rules of the Lent, rather than justify, argue and rationalize we should instead humble ourselves and acknowledge our shortcomings, and pray even harder for the strength to improve ourselves. As Dn. Abi Chacko (serving in our Church) shared, when we fall down we don't lie on the floor but rather pick ourselves up ... in the same manner, if we fail in our observation of the Lent than we must pray even harder and try again.
More so, when we fast as a Church together, we give strength to our own brothers and sisters to follow the fast joyfully.
1. On Fasting, from the homilies of St. John Chrysostom homilies "On Fasting"
2. Fasting to gain self-control, short video by Frederica Mathewes-Green
3. Questions and Answers about Orthodoxy, Orthodox Church of America