We performed multifrequency MRE in 10 controls and 88 patients underwent bariatric surgeries. A total of 38 patients were reassessed one year later with MRE and biopsy. At the initial exam, MRE-assessed loss modulus (imaginary component of the complex shear modulus) at 30Hz was significantly higher in obese patients compared with controls, even those without elevated liver fat. The elevation in loss modulus became normalized after treatment. In summary, MRE-assessed loss modulus shows promise as a sensitive indicator of early hepatic inflammation or cell injury in obese patients, pointing to a potential role in selection of patients for bariatric surgery.