Praise be to Allaah.
The Prophet’s guidance with regard to food is perfect guidance. It was described by Ibn al-Qayyim as follows:
When he put his hand in the food, he would say, “Bismillaah (in the Name of Allaah), and he told people to say this when eating. He said, “When any one of you eats, let him mention the name of Allaah. If he forgets to mention the name of Allaah at the beginning, let him say Bismillaahi fi awwalihi wa aakhirihi (in the name of Allaah at its beginning and at its end).” Saheeh hadeeth, narrated by al-Tirmidhi (1859) and Abu Dawood (3767).
The correct view is that it is obligatory to mention the name of Allaah (say Bismillaah) when eating. The ahaadeeth which state this are saheeh and are clear, with no contradictions in them.
When he raised the food to his mouth, he would say, “Al-hamdu Lillaahi hamdan katheeran tayyiban mubaarakan fihi ghayri makfiyyin wa laa muwadda’ wa laa mustaghni ‘anhu Rabbanaa ‘azza wa jall (Allaah be praised with an abundant, beautiful, blessed praise. He is the One Who is Sufficient, Who feeds and is never fed, The One Who is longed for, along with that which is with Him, and the One Who is needed. He is Our Lord, may He be glorified). Narrated by al-Bukhaari (5142).
He never criticized food at all. If he liked it, he would eat it, and if he did not like it, he would leave it and not say anything. Narrated by al-Bukhaari (3370) and Muslim (2064).
Or he would say, “I do not feel like eating this.” Narrated by al-Bukhaari (5076) and Muslim (1946).
Sometimes he would praise the food, as when he asked his family for food, and they said, “We have nothing but vinegar.” He asked for it and started to eat it, saying, “What a good food is vinegar.” Narrated by Muslim (2052)
He used to talk whilst he was eating, as is seen from the report quoted above about vinegar.
And he said to his step-son ‘Umar ibn Abi Salamah when he was eating with him: “Say Bismillaah and eat from that which is in front of you in the dish*.” Narrated by al-Bukhaari (5061) and Muslim (2022). [* At the time of the Prophet (peace and blessings of Allaah be upon him), people used to eat together from one dish, and children would sometimes forget the correct etiquette. - Translator]
He would repeatedly urge his guests to eat, as generous hosts do, and as is seen in the hadeeth of Abu Hurayrah, narrated by al-Bukhaari, about the story of drinking milk, where he repeatedly said to him, “Drink!” and he kept telling him to drink until he (the guest) said, “By the One Who sent you with the truth, I have no more room for it!” Narrated by al-Bukhaari (6087).
When he ate with others, he would not leave until he had made du’aa’ for them. He made du’aa in the house of ‘Abd-Allaah ibn Bisr, and said: “O Allaah, bless for them that which You have provided for them, forgive them and have mercy on them.” Narrated by Muslim (2042).
He commanded people to eat with their right hands and forbade them to eat with their left hands. He said, “The Shaytaan eats with his left hand and drinks with his left hand.” Narrated by Muslim (2020). This implies that eating with the left hand is haraam, and this is the correct view, because the one who eats with his left hand is either a shaytaan (a devil), or he is imitating the Shaytaan.
It was also reported in a saheeh hadeeth that he told a man who was eating with his left hand in his presence, “Eat with your right hand!” The man said, “I cannot.” He said, “May you never be able to!” – and the man never lifted his right hand to his mouth after that. Narrated by Muslim (2021). If it was permissible (to eat with the left hand), he would not have prayed against him for doing so. It was the man’s stubborn arrogance that made him refuse to obey the command, and this is the utmost disobedience which deserved this prayer against him.
He commanded those who complained that they never felt full to eat together and not separately, and to mention the name of Allaah (say Bismillaah) over the food so that He might bless it for them.” Narrated by Abu Dawood (3764) and Ibn Maajah (3286).
(See Zaad al-Ma’aad, 2/397-406)
It was also reported that he said, “I do not eat reclining.” Narrated by al-Bukhaari, 5083.
He used to eat using the first three fingers (of his right hand), which is the best way of eating.
See: Zaad al-Ma’aad, 220-222. And Allaah knows best.
The Prophet’s guidance regarding diet:
The Prophet (peace and blessings of Allaah be upon him) used to know what he was eating.
He used to eat what was good for him.
He used to eat enough to keep him going, but no so much as to make him fat. Ibn ‘Umar narrated that the Prophet (peace and blessings of Allaah be upon him) said: “The believer eats in one stomach whilst the kaafir eats in seven.” Narrated by al-Bukhaari (5081) and Muslim (2060).
He taught his ummah something to protect them from diseases caused by eating and drinking. He said: “The son of Adam does not fill any vessel worse than his stomach. It is sufficient for the son of Adam to eat a few mouthfuls, to keep him going. If he must do that (fill his stomach), then let him fill one third with food, one third with drink and one third with air.” Narrated by al-Tirmidhi (1381), Ibn Maajah (3349); classed as saheeh by al-Albaani in al-Silsilah al-Saheehah (2265).And Allaah knows best.