It is haram to break your without a valid excuse and whoever does not fast has abandoned one of the pillars of Islam, and is committing a grave major sin.

Muslims fast the month of Ramadan because Allah has commanded them to do so. Therefore, Muslims worship Allah through fasting which is beloved to Allah and which He has enjoined upon us.

Allah singled out fasting for Himself from all other good deeds, because of its honoured status before Him, because He loves it and because it is a demonstration of sincerity towards Him, as it is a secret between a person and his Lord, which no one can see except Allah.