The diet industry mines the deep seam of emotion that surrounds our eating habits to sell a precision-calibrated hope that morality, appearance, lifestyle, wellness—almost anything, really—can be improved if only we put different things in our mouth. Such advice usually nourishes insecurity more than it does the body. It turns out that the history of bad dieting advice is long and strange and full of charlatans out to profit from our gullibility. It’s also a perfect example of the old adage, “The more things change, the more they stay the same.” Harriet Fitch Little examines its evolution. This essay appeared in Kinfolk Issue Twenty-Six in Winter 2017.