Every act of goodness is rewarded. Rewards are given based on the sincerity of the intention. Fasting is the only worship about which Allaah Kareem has said that He Himself is the reward for it. This means that one develops such a close relationship with Almighty Allaah that Allaah Kareem Himself becomes the helper.
The Holy Prophet, [peace be upon him], said: “Allaah, the Lord of Honor and glory says: All other deeds of man are for himself, but his fasting is purely for Me and I shall reward him for it.