Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[190] Now Daniel and his kinsmen had resolved to use a severe diet, and to abstain from those kinds of food which came from the king's table, and entirely to forbear to eat of all living creatures. So he came to Ashpenaz, who was that eunuch to whom the care of them was committed, ¹ and desired him to take and spend what was brought for them from the king, but to give them pulse and dates for their food, and any thing else, besides the flesh of living creatures, that he pleased, for that their inclinations were to that sort of food, and that they despised the other. He replied, that he was ready to serve them in what they desired, but he suspected that they would be discovered by the king, from their meagre bodies, and the alteration of their countenances, because it could not be avoided but their bodies and colors must be changed with their diet, especially while they would be clearly discovered by the finer appearance of the other children, who would fare better, and thus they should bring him into danger, and occasion him to be punished; yet did they persuade Arioch, who was thus fearful, to give them what food they desired for ten days, by way of trial; and in case the habit of their bodies were not altered, to go on in the same way, as expecting that they should not be hurt thereby afterwards; but if he saw them look meagre, and worse than the rest, he should reduce them to their former diet. Now when it appeared that they were so far from becoming worse by the use of this food, that they grew plumper and fuller in body than the rest, insomuch that he thought those who fed on what came from the king's table seemed less plump and full, while those that were with Daniel looked as if they had lived in plenty, and in all sorts of luxury. Arioch, from that time, securely took himself what the king sent every day from his supper, according to custom, to the children, but gave them the forementioned diet, while they had their souls in some measure more pure, and less burdened, and so fitter for learning, and had their bodies in better tune for hard labor; for they neither had the former oppressed and heavy with variety of meats, nor were the other effeminate on the same account; so they readily understood all the learning that was among the Hebrews, and among the Chaldeans, as especially did Daniel, who being already sufficiently skillful in wisdom, was very busy about the interpretation of dreams; and God manifested himself to him.