But thou, when thou fastest, anoint thine head, and wash thy face; That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly. Matthew 6:17‭-‬18 KJV

Fasting does not impress God nor does the practice earn you points with Him. The discipline is between you and God and allows Him to change you for the good. The reward is the change He makes in you so that you see how He wants you to reach out to others as His ambassador.

But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him. Hebrews 11:6 KJV