Doctors have been telling fat people to eat less and exercise more for at least 2,500 years.

Here’s Hippocrates, father of Western medicine: “It is very injurious to health to take in more food than the constitution will bear, when, at the same time one uses no exercise to carry off this excess.”

And here’s the blunt advice of Polybus, student (and son-in-law) of Hippocrates: “Persons of a gross relaxed habit of body, the flabby, and red-haired, ought always to use a drying diet . . . Such as are fat, and desire to be lean, should use exercise fasting; should drink small liquors a little warm; should eat only once a day, and no more than will just satisfy their hunger.”

Public health experts no longer disparage red-haired folks,