In this study, we sought to examine the mu opioid receptor levels throughout the brain following RYGB surgery, and whether these changes are the result of caloric restriction or an effect of the surgery itself. Following the experiment, mu-opioid receptor autoradiography was performed on the rat brain using the [3H] [D-Ala2,N-Me-Phe4-Gly5-ol]- enkephalin (DAMGO) ligand. Two CSV files are uploaded giving the individual measurements of binding (uCi/g) for each region analyzed with ImageJ software. A third file gives the compiled averages used to perform statistical analysis and create binding figures. A sample film with regions drawn in ImageJ is provided. Body weight data recorded throughout the experiment is given in a CSV file as well.