Sayyiduna Anas رضى الله تعالى عنه narrates: the Messenger of Allah (peace be upon him) said: Have Suhoor (Seh-ree), for verily, in Suhoor, there is Barakah (blessings) (Bukhari/Muslim)
Su-hoor, refers to the food eaten before true dawn (Subh Saadiq).
It is preferable to delay Suhoor, till before the time of Fajr begin.
There are great virtues of Suhoor. The mercies of ALLAH TA’ALA descend and the Angels supplicate, for those who partake of Suhoor.
In many narrations, we are encouraged to have Suhoor, even if it is dates and water only.