Jesus tells us that when we fast, to do it privately.  When you are around people, don't complain about being hungry or mention that you are fasting.  Fasting and praying is a private thing between you and God.  If you tell others, just to get their praise or to hear them say what a good person you are, that makes Jesus very sad.

We want Jesus to live in us.  We want Jesus to share our lives
Our life with Jesus, is not a life of show. It is a life of being a better person and getting your reward from God, not from people.
Praying and fasting privately, just for God, makes Jesus very happy