It is highly recommended for Muslims to take their pre-dawn meal (as-suhoor) before beginning the day of fasting. The Prophet mentioned its blessings in several traditions.
Anas ibn Malik reported: The Messenger of Allah, peace and blessings be upon him, said:
تَسَحَّرُوا فَإِنَّ فِي السُّحُورِ بَرَكَةً
Take the morning meal, for verily, there is blessing in the morning meal.
Source: Sahih Bukhari 1823, Grade: Mutaffaqun Alayhi
Al-Miqdam ibn Ma'd reported: The Prophet, peace and blessings be upon him, said:
عَلَيْكُمْ بِغِذَاءِ السَّحَرِ فَإِنَّهُ هُوَ الْغِذَاءُ الْمُبَارَكُ
You must take the morning meal, for verily, it is a blessed meal.
Source: Musnad Ahmad 16741, Grade: Sahih
Irbad ibn Sariyah reported: I heard the Messenger of Allah, peace and blessings be upon him, inviting people to the morning meal during Ramadan and he would say:
هَلُمَّ إِلَى الْغَدَاءِ الْمُبَارَكِ
Come to the blessed breakfast.
Source: Sunan Abu Dawud 2344, Grade: Sahih
Abdullah ibn Harith reported: A man among the companions of the Prophet entered upon the Prophet while he was eating the morning meal. The Prophet, peace and blessings be upon him, said:
إِنَّهَا بَرَكَةٌ أَعْطَاكُمْ اللَّهُ إِيَّاهَا فَلَا تَدَعُوهُ
Verily, it is a blessing Allah has given you, so do not abandon it.
Source: Sunan An-Nasa'i 2162, Grade: Hasan
It is recommended to delay the morning meal as late as possible, because this makes it easier for Muslims to complete their fasting.
Abu Dharr reported: The Messenger of Allah, peace and blessings be upon him, said:
لَا تَزَالُ أُمَّتِي بِخَيْرٍ مَا عَجَّلُوا الْإِفْطَارَ وَأَخَّرُوا السُّحُورَ
My nation will not cease to be upon goodness so long as they hasten to break their fasting and delay the morning meal.
Source: Musnad Ahmad 20805, Grade: Sahih
It is permissible for Muslims to continue eating and drinking until redness appears on the horizon, which should occur just a few minutes after the first call to prayer (adhan) for the dawn prayer (fajr).
Abu Talaq reported: The Messenger of Allah, peace and blessings be upon him, said:
كُلُوا وَاشْرَبُوا وَلَا يَهِيدَنَّكُمْ السَّاطِعُ الْمُصْعِدُ وَكُلُوا وَاشْرَبُوا حَتَّى يَعْتَرِضَ لَكُمْ الْأَحْمَرُ
Eat and drink and let not the ascending white light stop you, so continue to eat and drink until redness appears on the horizon.
Source: Sunan At-Tirmidhi 705, Grade: Hasan
The Messenger of Allah would continue eating and drinking after the first call to prayer for as long as it would take to recite about fifty verses from the Quran, which is about a few minutes.
Zaid ibn Thabit reported: We ate the morning meal with the Prophet, peace and blessings be upon him, and then we stood for the prayer. It was asked, "How long was it between the two calls to prayer?" Zaid said:
قَدْرُ خَمْسِينَ آيَةً
It was time enough to recite fifty verses from the Quran.
Source: Sahih Bukhari 1821, Grade: Sahih
When a Muslim hears the first call to prayer, he should finish whatever food and drink he has in front of him.
Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:
إِذَا سَمِعَ أَحَدُكُمْ النِّدَاءَ وَالْإِنَاءُ عَلَى يَدِهِ فَلَا يَضَعْهُ حَتَّى يَقْضِيَ حَاجَتَهُ مِنْهُ
When one of you hears the call to prayer while his vessel is in his hand, let him not put it down until he fulfills his needs from it.
Source: Sunan Abu Dawud 2350, Grade: Sahih
However, it is very important to eat moderately when taking the morning meal and breaking the fast.
Allah said:
يَا بَنِي آدَمَ خُذُوا زِينَتَكُمْ عِندَ كُلِّ مَسْجِدٍ وَكُلُوا وَاشْرَبُوا وَلَا تُسْرِفُوا ۚ إِنَّهُ لَا يُحِبُّ الْمُسْرِفِينَ
O children of Adam, take your adornment at every mosque and eat and drink, but be not excessive. Verily, He likes not those who commit excess.
Surah Al-A'raf 7:31
Ibn Umar reported: The Prophet, peace and blessings be upon him, said:
الْكَافِرُ يَأْكُلُ فِي سَبْعَةِ أَمْعَاءٍ وَالْمُؤْمِنُ يَأْكُلُ فِي مِعًى وَاحِدٍ
The unbeliever eats with seven intestines, and the believer eats with one intestine.
Source: Sahih Muslim 2060, Grade: Sahih
Atiyyah ibn Amr reported: Salman Al-Farisi disliked eating too much food and he said he heard the Messenger of Allah, peace and blessings be upon him, say:
إِنَّ أَكْثَرَ النَّاسِ شِبَعًا فِي الدُّنْيَا أَطْوَلُهُمْ جُوعًا يَوْمَ الْقِيَامَةِ
Verily, the people who eat their fill the most in this world will be the most hungry on the Day of Resurrection.
Source: Sunan Ibn Majah 3351, Grade: Sahih
The prophetic tradition (sunnah) is to fill the stomach with one-third for food, one-third for drink, and one-third be left empty.
Al-Miqdam ibn Ma'd reported: The Messenger of Allah, peace and blessings be upon him, said:
مَا مَلَأَ آدَمِيٌّ وِعَاءً شَرًّا مِنْ بَطْنٍ حَسْبُ الْآدَمِيِّ لُقَيْمَاتٌ يُقِمْنَ صُلْبَهُ فَإِنْ غَلَبَتْ الْآدَمِيَّ نَفْسُهُ فَثُلُثٌ لِلطَّعَامِ وَثُلُثٌ لِلشَّرَابِ وَثُلُثٌ لِلنَّفَسِ
There is no vessel which the son of Adam can fill more evil than his stomach, for it is sufficient for him to take a few mouthfuls in order to straighten his back, but if he must, then fill one-third with food, one-third with drink, and one-third with breath.
Source: Sunan Ibn Majah 3349, Grade: Sahih
Therefore, every Muslim should take the morning meal before fasting due to its blessings. He should delay the morning meal as late as possible, which is about a few minutes after the first call to prayer before the Fajr prayer. He should eat moderately and avoid extravagance in consumption.