Dr. Sera Young is a faculty member in the Division of Nutritional Sciences at Cornell University, and a Reproductive Infectious Disease Fellow at the University of California, San Francisco. Her book is Craving Earth: Understanding Pica -- the Urge to Eat Clay, Starch, Ice and Chalk. Pregnant women or those with nutritional deficiencies usually engage in Pica. Read more from the NIH. Dr. Young mentions the engaged group of people who eat ice (a type of Pica), and who like a certain type of ice made at Sonic Burger.