Fasting protects Chastity and reduces urges and desires..

 Messenger of Allaah (peace and blessings of Allaah be upon him) said to us, ‘O young men, whoever among you can afford to get married, then let him do so, for it is more effective in lowering the gaze and guarding chastity. And whoever is not able to do that, then let him fast, for that will be a shield for him.’” (al-Bukhaari, 5066; Muslim, 1400). Fasting reduces the effects that desires have on young people.