Anas (May Allah be pleased with him) reported:
Abu Talhah (May Allah be pleased with him) said to (to his wife) Umm Sulaim(May Allah be pleased with her), "I noticed some weakness in the voice of Messenger of Allah (PBUH) and I feel it was due to hunger. Have you got any food?'' She said, "Yes.'' So she brought out barley loaves, took off her head covering, in a part of which she wrapped these loaves and then put them beneath my mantle and covered me with a part of it. She then sent me to Messenger of Allah (PBUH). I set forth and found Messenger of Allah (PBUH) sitting in the mosque in the company of some people. I stood near them whereupon Messenger of Allah (PBUH) asked, "Has Abu Talhah sent you?'' I said, "Yes.'' Thereupon he said to those who were with him to get up (and follow him). He went forth and so did I, ahead of them until I came to Abu Talhah and informed him. Abu Talhah said, "O Umm Sulaim, here comes Messenger of Allah (PBUH) along with the people and we do not have enough (food) to feed them.'' She said, "Allah and His Messenger know better.'' Abu Talhah went out (to receive him) until he met Messenger of Allah (PBUH), and he came forward along with him until they both (Messenger of Allah (PBUH) and Abu Talhah (May Allah be pleased with him) came in. Then Messenger of Allah (PBUH) said, "O Umm Sulaim, bring forth what you have with you.'' So she brought the bread. Messenger of Allah (PBUH) commanded that the bread be broken into small pieces and after Umm Sulaim (May Allah be pleased with her) had squeezed clarified butter out of a butter container and made it just like soup. Messenger of Allah (PBUH) recited over it what Allah wished him to recite. He then said, "Allow ten guests to come in.'' They ate until they had their fill. They then went out. He (Messenger of Allah (PBUH)) again said, "Allow ten (more to come in)'', and he (the host) ushered them in. They ate to their fill. Then they went out. He (PBUH) again said, "Allow ten (more),'' until all the people ate to their fill. They were seventy or eighty persons.  
[Al-Bukhari and Muslim].

Another narration is: Anas said: When all had eaten, the remaining food was collected. It was as much as there was in the beginning.

Yet another narration is: Anas said: The groups of ten people ate by turn. After eighty persons had eaten, Messenger of Allah (PBUH) and the family of that house ate, and there was still a quantity left over.

Another narration is: Anas (May Allah be pleased with him) said: I visited Messenger of Allah (PBUH) one day, and found him sitting in the company of his Companions, with a belt tied over his waist. I asked, "Why has Messenger of Allah (PBUH) tied the belt on his waist?'' I was told, "Due to hunger.'' I went to Abu Talhah (May Allah be pleased with him) the husband of Umm Sulaim (May Allah be pleased with her) and said, "O father, I have seen Messenger of Allah (PBUH) with a belt tied over his waist. I asked one of his Companions about the reason of it and he said that it was on account of severe hunger.'' Abu Talhah (May Allah be pleased with him) went to my mother and asked, "Have you got anything?'' She said, "Yes. I have a piece of bread and some dry dates. Were Messenger of Allah (PBUH) to come alone, we could feed him his fill, but if he comes along with others, there would not be enough food.'' Anas then narrated the Hadith in full.

Taken from Riyad-us-Saleheen, Chapter 56