• Hypothesis 2: (a) Increased brain activity in response to visual presentation of food stimuli, using functional magnetic resonance imaging (fMRI), will be seen in Ls and Lm compared to Ns and Nm in the insula and the orbitofrontal cortex. Enhanced neuronal activity in response to foods will be most pronounced in the Ls/Lm phase (Ns/Nm<Ls/Nm≤Ns/Lm<Ls/Lm). (b) Neuronal responses to food stimuli will be related to pre-test neuropeptide Y (NPY), hypocretin-1, and subsequent food intake.