2. And the Prophet (صلى الله عليه وسلم) said: "Bilaal gives the adhaan at night, so eat and drink until you hear the adhaan of Ibn Umm Maktoom, for he does not give the adhaan until dawn comes." This imsaak which some of the people do is an addition to that which Allaah has enjoined, so it is false. It is a kind of extremism in religion, and the Prophet (peace and blessings of Allaah be upon him) said: "Those who go to extremes are doomed, those who go to extremes are doomed, those who go to extremes are doomed." Narrated by Muslim, 2670
Al-Nawawi (may Allaah have mercy on him) said: "This shows that it is permissible to eat, drink, have intercourse etc
until dawn comes."
Al-Haafiz ibn Hajar said in Fath al-Baari (4/199): "One of the reprehensible innovations that have appeared in our times is giving the second adhaan approximately twenty minutes before Fajr in Ramadaan, and extinguishing the lamps which indicate that it is haraam to eat and drink for those who want to fast. Those who introduced this innovation claim that they are erring on the side of caution with regard to an act of worship."
What is obligatory on all Muslims is that they hold on firmly to the Qur'an and Sunnah and follow it as closely as one can. This is a safeguard for us, so that we don't fall right or left but stay on the middle course. The Prophet (صلى الله عليه وسلم) described the religion of Islaam that is a middle course between extreme and lenient. Remember these words of the Prophet (صلى الله عليه وسلم): I leave behind me two things. You will never go astray if you hold fast to them: The Qur'an and my Sunnah.
O Allah! Render the thoughts and inclinations within my heart, to be Your fear and remembrance, and let my endeavour and desire be devoted to what You love and appreciate. Keep my feet firm on Thy Right Path so that I should not stagger, and guide me to the true Faith so that I should not go astray. Ameen!!!
Source : http://www.calgaryislam.com/imembers/displayarticle542.html (link no longer working)
For more about the practice of taking a sahoor (pre-dawn meal before fasting) as well as ideas for sahoor, see:
my Sahoor post