Praise be to Allah.
Gluttony is one of the greatest sins that lead to doom and it causes many diseases and sicknesses, both spiritual and physical, because it leads to sexual desire, then the desire for status and wealth in order to fulfil the first two desires. Then that generates spiritual diseases such as showing off, destructive envy (hasad), boastfulness and arrogance because of being focused on worldly matters. In most cases that leads to evil and immorality, all of it because of this desire. The Arabs of old said: The stomach is the home of disease and restraint is the basis of the remedy.
Allaah says (interpretation of the meaning):
“and eat and drink but waste not by extravagance, certainly He (Allaah) likes not Al‑Musrifoon (those who waste by extravagance)”
The Sunnah encourages moderation in eating, and strongly criticizes extravagance.
The Prophet (peace and blessings of Allaah be upon him) 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 (2380); classed as saheeh by al-Albaani in al-Silsilah al-Saheehah (2265).
It was narrated that Naafi’ said: Ibn ‘Umar used not to eat until a poor man was brought to eat with him. I brought a man in to eat with him and he ate a great deal. He said: O Naafi’, do not let this man enter upon me, for I heard the Messenger of Allaah (peace and blessings of Allaah be upon him) say: “The kaafir eats in seven intestines.” Narrated by al-Bukhaari (5393) and Muslim (2060).
Al-Nawawi said, commenting on this hadeeth (14/25):
The scholars said: What the hadeeth means is to be content wit little in this world and encouraging asceticism and contentment, in addition to the fact that eating little is a good characteristic, and eating a great deal is the opposite. As for the words of Ibn ‘Umar concerning the poor man who ate a great deal in his presence, “Do not let him enter upon me,” he only said that because he was behaving like a kaafir, and if a person is behaves like a kaafir it is makrooh to mix with him unnecessarily; moreover, the amount that this man ate could had fed a number of people. End quote.
We have quoted other ahaadeeth on this topic elsewhere on our site; please see question no. 71173.
Ibn al-Qayyim (may Allaah have mercy on him) has summed up for us the teaching of the Prophet (peace and blessings of Allaah be upon him) with regard to food and drink, which he derived from the saheeh ahaadeeth. He says in Zaad al-Ma’aad (1/147):
Similarly the practice of the Prophet (peace and blessings of Allaah be upon him) was not to reject what was available, and not to go out of his way to seek that which was not available. No good food was brought to him but he ate it, unless he had no appetite for it, in which case he left it but did not forbid it. He never criticized any food. If he wanted it he ate it, otherwise he would leave it, as he refrained from eating lizard meat because he was not used to it, but he did not forbid it to the ummah. He ate sweets and honey, which he liked. He ate camel meat, mutton, chicken, bustard, onager, rabbit and seafood. He ate grilled meat and both fresh and dry dates. … He did not refuse good food, and he did not go out of his way to seek it, rather he would eat what was available, but if it was not available he would be patient, and he would tie a stone to his stomach because of hunger. Three new moons in a row would be sighted, and no cooking fire would be lit in his house. End quote.
The scholars have mentioned the benefits of moderation in food and not being extravagant. These include:
1 – Purity of heart, mental alertness and deep insight. Satiety generates stupidity and blinds the heart. Hence the proverb says “The one whose stomach is hungry will become able to think deeply and his intelligence will honed.”
2 – Humility and the loss of pride, joy and insolence, which are the foundation of tyranny and neglect of Allaah.
3 – One does not forget the wrath and punishment of Allaah, or the people who are afflicted by calamity. For the one who has his fill forgets the one who is hungry and he forgets hunger, but the one who is smart does not see someone else afflicted by a calamity but he is reminded of calamity in the Hereafter.
4 – One of the greatest benefits is that it puts an end to all sinful desires, and brings control over the self that is inclined towards evil, because the source of all sins is desires and energy, and the fuel for energy and desires is food. Dhu’l-Noon said: I never ate my fill but I sinned or thought of sinning.
5 – Warding off sleep and being able to stay up. For the one who eats a lot will drink a lot, and the one who drinks a lot will sleep a lot. Sleeping a lot wastes one’s time and causes one to miss out on tahajjud; it makes one slow and hardens the heart. Time is the most precious gift and it is the person’s capital, but sleep is death and sleeping too much shortens one’s life.
6 – Physical health and warding off disease, which is caused by eating too much and mixing foods in the stomach. The doctors say that gluttony is the cause of disease and restraint leads to a cure.
Summarized from Ihya’ ‘Uloom al-Deen (3/103-104).
With regard to the ahaadeeth mentioned in the question, none of them are saheeh.
The first hadeeth:
‘Aa’ishah (may Allaah be pleased with her) said: “The first calamity for this ummah after the death of its Prophet (peace and blessings of Allaah be upon him) will be satiety, for when people’s stomachs are full, their bodies will grow fat, and their hearts will become weakened and their desires will grow wild.” Narrated by al-Bukhaari in al-Du’afa’ – as attributed to him by al-Dhahabi in Meezaan al-I’tidaal (3/335). Also narrated by Ibn Abi’l-Dunya in al-Joo’ (no. 22).
Narrated via Ghassaan ibn ‘Ubayd al-Azdi al-Mawsili, who said: Hamzah al-Basri told us, from Hishaam ibn ‘Urwah, from his father, from ‘Aa’ishah.
I say: This isnaad is da’eef jiddan (very weak) because of Ghassaan ibn ‘Ubayd, in whose biography in Lisaan al-Mizaan (4/418) it says: Ahmad ibn Hanbal said: We wrote from him, then he came to us here then I burned what I wrote from him. Ibn ‘Adiyy said: The weakness in his hadeeth is obvious. According to a report from Yahya ibn Ma’een, it is da’eef. … Then he counted the hadeeth of ‘Aa’ishah that we have as being munkar. End quote.
Hence Shaykh al-Albaani said in Da’eef al-Targheeb (1239): It is munkar mawqoof. End quote.
Note: In the question this hadeeth is attributed to al-Bukhaari, and this is a serious mistake, because saying that a report “was narrated by al-Bukhaari” usually means that it is from his Saheeh, but al-Bukhaari wrote many other books, in which he narrated ahaadeeth with their isnaads, but they are not necessarily saheeh, such as his book al-Du’afa’ al-Sagheer, which has been printed, and al-Du’afa’ al-Kabeer, which was mentioned by Ibn al-Nadeem and Brockelmann in Tareekh al-Adab (p. 65), and which still exists in the library of Patna in India. If it so happened that al-Bukhaari narrated a hadeeth in any of his books apart from al-Saheeh, which is the greatest book written by a scholar in Islam, then it should be stated when quoting the hadeeth: “narrated by al-Bukhaari in al-Taareekh” or “in al-Du’afa’” or “in al-Adab al-Mufrad” for example, then one should research the isnaad of the hadeeth: is it saheeh or not, as is done in other books.
This hadeeth of ‘Aa’ishah may be in al-Du’afa’ al-Kabeer. We have looked for it in al-Sagheer but I could not find it. al-Du’afa’ al-Sagheer rarely mentions ahaadeeth and isnaads. And Allaah knows best.
The second hadeeth: It was narrated from Anas ibn Maalik (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “It is extravagance to eat everything you want.” Narrated by Ibn Majaah (3352); Abu Ya’laa in al-Musnad (5/154); Abu Nu’aym in al-Hilyah (10/213); al-Bayhaqi in Shu’ab al-Eemaan (5/46) and others, via Baqiyah ibn al-Waleed, Yoosuf ibn Abi Katheer told us, from Nooh ibn Dhakwaan from al-Hasan from Anas in a marfoo’ report (i.e., attributed to the Prophet (peace and blessings of Allaah be upon him)).
This isnaad is da’eef jiddan (very weak) and has a number of faults, such as:
1 – Yoosuf ibn Abi Katheer, of whom Ibn Hajar said in Tahdheeb al-Tahdheeb (11/421): One of the Shaykhs of Baqiyah who are not known. End quote.
2 – Nooh ibn Dhakwaan, whose hadeeth is munkar. It says in his biography in Tahdheeb al-Tahdheeb:
Ibn ‘Adiyy said: His ahaadeeth are not sound. Ibn Hibbaan said: His hadeeth is munkar jiddan and his hadeeth should not be narrated. Abu Nu’aym said: he narrated problematic reports from al-Hasan, and he has a document from al-Hasan from Anas. End quote.
Hence the hadeeth was classed as da’eef (weak) by more than one of the scholars: Ibn Hibbaan in al-Majrooheen (3/47); Ibn ‘Adiyy in al-Kaamil (8/299); Ibn al-Jawzi in al-Mawdoo’aat (3/182); al-Busayri in Misbaah al-Zujaajah (2/188); al-Sakhkhaawi in al-Maqaasid al-Hasanah (515).Shaykh al-Albaani said in al-Silsilat al-Da’eefah (no. 241): It is mawdoo’ (fabricated).
The saheeh ahaadeeth quoted above are sufficient and we have no need of these two weak ahaadeeth. The one who wants to know more about this topic may refer to al-Joo’ by Ibn Abi’l-Dunya; Mukhtasar Minhaaj al-Qaasideen by Ibn Qudaamah; Zaad al-Ma’aad by Ibn al-Qayyim and Sharh Riyaadh al-Saaliheen by Shaykh Ibn ‘Uthaymeen.
See also the answer to question no. 6503.
And Allaah knows best.