In a crossover design , 22 healthy , nonobese adults ( 17 men ) underwent a functional magnetic resonance imaging ( fMRI ) food-picture evaluation task after a 16-h overnight fast ( Fasted-Saline ) or after eating breakfast 95 min before scanning ( 730 kcal , 14 % protein , 31 % fat , and 55 % carbohydrate ) and receiving a saline ( Fed-Saline ) or acyl ghrelin ( Fed-Ghrelin ) subcutaneous injection before scanning .