Sayyiduna Anas bin Malik (may Allah be pleased with him) said: The cavalry of the Messenger of Allah (peace and blessings be upon him) raided us, so I went to the Messenger of Allah (peace and blessings be upon him) while he was eating. He (peace and blessings be upon him) said: "Sit down and eat from our food." I said: I am fasting. He (peace and blessings be upon him) said: "Sit down, I will tell you about prayer and fasting: Allah Almighty has relieved the traveller of half of the prayer, and has relieved the traveller and the nursing woman of fasting." So I reproached myself for not having eaten from the food of the Messenger of Allah (peace and blessings be upon him).
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 762