How the muffin, and specifically its once-proud top, went from a favorite food to a fashion faux pas — as in that roll of flesh hanging over your low-rise jeans — has a lot to do with what’s in it.

“The story of what’s happened to the American muffin over the last 20 years is really the history of sugar,” says food historian Betty Fussell, author of “Masters of American Cookery.” “Muffins have become sweeter and now we think of them that way,” she says.