I may give an answer no one would expect, but I believe this is what is found in holy Scripture.

Fasting is good and acceptable to God only when it is focused completely and entirely upon Him.

Fasting is for the express purpose of surrendering ourselves wholly and completely to God. Fasting should be a vehicle that opens the door to a deeper understanding of who God is and what matters to Him. The result of the fast should be a stronger relationship with God that changes the way we relate to others. This is what Isaiah the Prophet meant about fasting.

“Is this the kind of fast I have chosen, only a day for people to humble themselves? Is is only for bowing one’s head like a reed and for lying in sackcloth and ashes? Is that what you call a fast, a day acceptable to the Lord?” (Isaiah 58:5).

God answered His own question about the fast that pleases HIm: “Is it not to share your food with the hungry and to provide the poor wanderer with shelter–when you see the naked, to clothe them and not to turn away from your own flesh and blood?” (Isaiah 58:7).

That kind of fast pleases God and blesses the entire nation: “Then your light will break forth like the dawn, and your healing will quickly appear, then your righteousness will go before you, and the glory of the Lord will be your rear guard” (Isaiah 58:8).

Sometimes in the Bible fasting also includes a time of mourning for the sinfulness and rebellion of God’s people. You can see immediately that that kind of mourning would naturally include a desire to please God.

If you fast for these reasons, fasting is good and acceptable. It will also be beneficial for your growing relationship with God.

There are other reasons to fast which Jesus soundly condemned.

Fasting should never be about other people. In fact, Jesus said when you fast “keep it to yourself.” Instead of making it known you are fasting, simply keep that between you and God. It is so easy to do religious things in order to be “seen of men.”

Fasting should not be because there is a an expectation that you will fast. If we fast because others fast, we will miss the significance of what God can do when we yield ourselves to Him.

Fasting should not be trivial. Many people make it a trivial event where God is not even considered. If you are going to give up something for Lent, why not spend a significant amount of time asking God what you should change (and not for a season but for a lifetime)?

Fasting should be a time of intense communion with God, when everything centers around Him.

When we give our whole lives to God, recognizing that everyday matters to Him we please God with a fast. When we seek God’s forgiveness and mourn over our sinfulness, we please God with a fast. When we care about the people God cares about, we please God in a fast. When we ask what He would change about our lives, we please God with a fast.

Fast in this way, devoted completely to God with a desire to know Him and please Him, and you will be blessed.