Becky is 19 years old and in her second year of college. Recently, she has become obsessed with exercise. Becky has discovered that she can eat as much as she wants of whatever she wants in biweekly binges as long as she exercises excessively. When she does this, she does not gain any weight and she is finding that it helps with her looks. In fact, she loves all the compliments she's receiving from her friends about how great she looks these days. Becky would MOST likely be diagnosed with: