A question on christian fasting?

A friend of mine asked about fasting and now I’m thinking about it.
God’s grace has forgiven us all sins so why fast? Does it have a real purpose? Does it do any good?

the Godly fast according to Scripture is valuable in seeking more serious things from God. It is also healthy in the natural sense. But going hungry and calling a fast is ludicrous.
1 Cor 7:5 says “..give yourselves to fasting…” this usually is connected to prayer. By Fasting and Praying we can move the hand of God. Matt 17:21 Jesus teaching says that “..nothing will be impossible for you. However, this kind does not go out “except” by prayer and fasting…”
Jesus taught the right way to fast in Matt 6:16-18
Isaiah also has teaching on fasting in Ch 58

Christian Fasting – The Wrong & Right Reasons to Fast