The purpose of this study is to examine how light exposure and meal timing influences circadian rhythms in healthy people. We are looking for healthy men and women, ages 17-40 to participate in a study at the University of Colorado-Boulder Sleep and Chronobiology Laboratory. The study is 7 weeks long with 8 in-person visits. Participants live in the sleep laboratory on two separate occasions for 7.7 days (15.4 days total). Main procedures involved: Health screening Monitor on two separate occasions your sleep for 2 weeks and blood sugar levels for 3 days at home Live in the sleep laboratory on two separate occasions for 7.7 days (15.4 days total): Blood and saliva sampling Reaction time and ability to think testing Bright light exposure and earlier meal timing Compensation is up to $4,093. Go to https://redcap.link/fmigb271 for study details and to apply. If you have additional questions or are unable to complete the survey on-line, please call us at 303-735-1923 (M-F, 9am-5pm).