The Liu lab will investigate how animals select specific types of foods to satisfy their changing nutritional needs. In an unpredictable environment containing a variety of different foods, animals must consider not only how much to eat, but what type of nutrients to consume. To navigate this process of selection, animals must balance their general feelings of hunger with any “cravings” they might experience for a meal rich in proteins, fats, sugars, or salt. As a postdoctoral fellow, I discovered a neural circuit that controls protein intake in fruit flies—the first protein-specific hunger switch to be studied in any animal. Now, combining this system with powerful methods in cell and molecular genetics, neurobiology, and behavior, I will map and dissect the genetic and neural circuits that control flies’ hunger for sugars and fats, and examine whether activation of these systems alters the animals’ consumption of proteins. These findings will illuminate how animals balance diet and nutrition and could point toward novel therapies for treating eating disorders that lead to nutritional imbalance.