From G.K. Chesterton's St. Thomas Aquinas: The Dumb Ox, a splendid little book about a very big fellow indeed. Everyone knows this anecdote, probably, but it's too good to pass up today:

But Thomas came very unwillingly, and, if we may say it of so kindly a man, rather sulkily. As he entered Paris they showed him from the hill that splendour of new spires beginning, and somebody said something like, "How grand it must be to own all this." And Thomas Aquinas only muttered, "I would rather have that Chrysostom MS. I can't get hold of."

Somehow they steered that reluctant bulk of reflection to a seat in the royal banquet hall; and all that we know of Thomas tells us that he was perfectly courteous to those who spoke to him, but spoke little, and was soon forgotten in the most brilliant and noisy clatter in the world: the noise of French talking. What the Frenchmen were talking about we do not know; but they forgot all about the large fat Italian in their midst, and it seems only too possible that he forgot all about them. Sudden silences will occur even in French conversation; and in one of these the interruption came. There had long been no word or motion in that huge heap of black and white weeds, like motley in mourning, which marked him as a mendicant friar out of the streets, and contrasted with all the colours and patterns and quarterings of that first and freshest dawn of chivalry and heraldry. The triangular shields and pennons and pointed spears, the triangular swords of the Crusade, the pointed windows and the conical hoods, repeated everywhere that fresh French medieval spirit that did, in every sense, come to the point. But the colours of the coats were gay and varied, with little to rebuke their richness; for Saint Louis, who had himself a special quality of coming to the point, had said to his courtiers, "Vanity should be avoided; but every man should dress well, in the manner of his rank, that his wife may the more easily love him."

And then suddenly the goblets leapt and rattled on the board and the great table shook, for the friar had brought down his huge fist like a club of stone, with a crash that startled everyone like an explosion; and had cried out in a strong voice, but like a man in the grip of a dream, "And that will settle the Manichees!"

Incidentally, while much humorous hay has been made of the fact St. Thomas probably...um...had to get his cappa at the Medieval Big and Tall Store (i.e., the question of how the meditating, levitating Thomas might fit into the question of whether God can make an object so big He cannot lift it, or for that matter, his nickname of the "Dumb Ox"), I've never heard any reference to his eating habits. In fact, I would assume him to be rather on the abstemious side of things, which makes me wonder if he had some sort of metabolism problem. Or maybe he just didn't have time to get out much. But anyway, never trust a skinny Dominican, as the Cnytr says.