hippocratic regimen
Food, exertion, sleep and the time of year are set against one another and adjusted together: exertion answered with food, food with exertion, and both read against the season and the person's own constitution. The Hippocratic On Regimen is given over to this, and its argument is that no single element is the lever — the balance is. It is the oldest position in this collection on questions we now ask one nutrient at a time.