From that greater clearness of head and quicker apprehension which usually attend temperance in eating and drinking

What a remarkable man, Benjamin Franklin. From The Autobiography of Benjamin Benjamin Franklin.

When about 16 years of age I happened to meet with a book, written by one Tryon, recommending a vegetable diet. I determined to go into it. My brother, being yet unmarried, did not keep house, but boarded himself and his apprentices in another family. My refusing to eat flesh occasioned an inconveniency, and I was frequently chid for my singularity. I made myself acquainted with Tryon's manner of preparing some of his dishes, such as boiling potatoes or rice, making hasty pudding, and a few others, and then proposed to my brother, that if he would give me, weekly, half the money he paid for my board, I would board myself. He instantly agreed to it, and I presently found that I could save half what he paid me. This was an additional fund for buying books. But I had another advantage in it. My brother and the rest going from the printing-house to their meals, I remained there alone, and, dispatching presently my light repast, which often was no more than a bisket or a slice of bread, a handful of raisins or a tart from the pastry-cook's, and a glass of water, had the rest of the time till their return for study, in which I made the greater progress, from that greater clearness of head and quicker apprehension which usually attend temperance in eating and drinking.

And now it was that, being on some occasion made asham'd of my ignorance in figures, which I had twice failed in learning when at school, I took Cocker's book of Arithmetick, and went through the whole by myself with great ease. I also read Seller's and Shermy's books of Navigation, and became acquainted with the little geometry they contain; but never proceeded far in that science. And I read about this time Locke On Human Understanding, and the Art of Thinking, by Messrs. du Port Royal.