Sleek-headed men, and such as sleep o' nights.
Yond Cassius has a lean and hungry look;
He thinks too much: such men are dangerous."
Is Caesar's observation apt? There are recent studies to show that too healthy an appetite may impede one's thinking. The history of philosophy perhaps inadvertently confirms this too. I cannot bring to mind any great thinkers who were obese in the medical sense. The closest figure who might "fit" the diagnosis would appear to be Thomas Aquinas, who was referred to as "the dumb Sicilian ox" due to his stout appearance and slow action. His portrait's are certainly not the most flattering either.
|St. Thomas Aquinas|
To the scholar and intellectual, the delicacies at the table of the mind have always surpassed those of the phenomenal world, or so it would seem. And this perhaps fits a pattern of disinterest in all things of the material world, the pleasures of the flesh included. Once the ambrosia of the gods has been tasted, all human food turns to ashes in the mouth. Like Tantalus, such food one seeks to share rather than hoard away, like the secrets of the Olympians.
It may also be merely correlation not causation which explains this. Philosophy is certainly not a vocation which promises worldly wealth, and those who have consciously decided to dedicate their lives to her have long recognized the need to economize if they are to have the leisure to think. Following his own principles of economy, Spinoza often dined upon a gruel or a milk soup he made himself. Epicurus lived on such a frugal diet, he famously wrote a friend: "Send me a pot of cheese, so that I may have a feast when I care to."
Among modern philosophers, my personal favorite John Rawls, gives the appearance of never having eaten anything at all, which perhaps recommends him as the thinker best suited to understand the plight of the poor. Bertrand Russell certainly never cut anything but a skeletal shape, even when young, and today might have lead to rumors of an eating disorder. It always was important for him to keep a trim figure for the ladies. The list could perhaps be extended indefinitely.
Is there some connection between calories and cogitation? I can't say, but it's certainly food for thought.