Rebecca Gerson says she has never had a good relationship with food. “One day, I just felt uncomfortably full,” she remembers, “so I purged, and it kind of just stuck.” Gerson was twelve years old. Within a few years, she had cut most foods out of her diet but kept a short mental list of “safe” options: brown rice, strawberries, oatmeal, a single brand of veggie burgers.
When, four years ago, she downloaded MyFitnessPal Calorie Counter and Diet Tracker to her iPhone, it seemed at first like a new tool that could help her gain control over her eating. The free app, which allows users to enter (or even scan the barcodes of) more than three million foods, calls itself the largest nutritional database in the world. Along with calculating the fat, sodium, carbohydrates, and protein in everything from raw celery to Egg McMuffins to restaurant-prepared shark-fin soup, MyFitnessPal users can input their physical activity, which is automatically converted into caloric expenditure. As Gerson began using the app more and more intensely, she found her list of “safe” foods shrinking. “It’s really easy to keep rigid track of everything you do,” Gerson says. “I started to become rigid on foods I’d never had to think about before. Nothing’s really OK anymore because everything ‘counts.’ ”