Fasting from food is a controversial, dangerous, and yet utterly normal human practice. Christine Baumgarthuber discusses our fascination with restrictive eating in cultural history from her new book, Why Fast? If fasting offers few health benefits, why do people fast? Why have we always fasted? Does fasting speak to something deep and immutable within us? Why are our bodies so well adapted to intermittent fasting? And, what might this ancient, ascetic ritual offer us today?