The Deipnosophists (2.26)

But that water is undeniably nutritious is plain from the fact that some animals are nourished by it alone, as for instance, grasshoppers. And there are many other liquids which are nutritious, such as milk, barley-water, and wine. At all events, animals at the breast are nourished by milk; and there are many nations who drink nothing but milk. And it is said that Democritus, the philosopher of Abdera, after he had determined to rid himself of life on account of his extreme old age, and when he had begun to diminish his food day by day, when the day of the Thesmophorian festival came round, and the women of his household besought him not to die during the festival, in order that they might not be debarred from their share in the festivities, was persuaded, and ordered a vessel full of honey to be set near him: and in this way he lived many days with no other support than honey; and then some days after, when the honey had been taken away, he died. But Democritus had always been fond of honey; and he once answered a man, who asked him how he could live in the enjoyment of the best health, that he might do so if he constantly moistened his inward parts with honey, and his outward man with oil. And bread and honey was the chief food of the Pythagoreans, according to the statement of Aristoxenus, who says that those who eat this for breakfast were free from disease all their lives. And Lycus says that the Cyrneans (and they are a people who live near Sardinia) are very long-lived, because they are continually eating honey; and it is produced in great quantities among them.