Umm Mubashshir al-Ansariyyah (may Allah be pleased with her), who was one of the maternal aunts of the Prophet (peace and blessings be upon him), says that the Prophet (peace and blessings be upon him) and Sayyiduna Ali (may Allah be pleased with him), who had been weakened by illness, came to our house, and a bunch of dates was hanging there. The Prophet (peace and blessings be upon him) ate some dates from it. When Sayyiduna Ali (may Allah be pleased with him) began to take some, he (peace and blessings be upon him) said: "You are weak; this does not suit your constitution, leave it." So I cooked barley and chard and presented it to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "O Ali! Eat, this is beneficial for you."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19561