4. An MRI-determined fat fraction classification threshold (≥5%) will be used to confirm subjects. MR examinations will include four research sequences (three imaging sequences and one single-voxel spectroscopy sequence) that have been developed and refined by Dr. Sirlin, allowing for the measurement of liver fat fraction and newer candidate MR biomarkers for future NAFLD studies. MR examinations will last 20-30 minutes and will be performed without contrast agents. Subjects will be scanned at 1.5T. To assess sequence repeatability, two sequences per subject, block randomized, will be run three times. For MR elastography, MR imaging will be done which will include placing a vibrating paddle over the abdomen while images are obtained. A comprehensive screening questionnaire will be utilized prior to subjects having an MRI. Experienced research MR technologists will perform MR examinations under the supervision of Dr. Sirlin.