The investigators will recruit 30 subjects with severe obesity scheduled for bariatric surgery and 30 healthy-weight controls.
Following written informed consent, the investigators will collect the study subject's medical information, conduct a dietary and quality-of-life survey, take body measurements, obtain scalp photos, perform a hair-pull test, collect a hair sample, and conduct muscle strength testing. Controls will be assessed only at baseline. Those with severe obesity will return at 4 ± 2 weeks, 12 ± 4 weeks, and 26 ± 4 weeks following bariatric surgery to repeat the study procedures.