Background Weight regain after weight loss is common. The impact on cardiometabolic risk factors is not well established. Methods and Results Publicly available data were analyzed from participants of the Look AHEAD (Action for Health in Diabetes) trial with ≥3% initial weight loss (n=1561) during a 1-year intensive lifestyle intervention and with year 4 follow-up data. Participants who regained (regainers) or maintained (maintainers) weight loss were defined with 5 dichotomized cut points (0%, 25%, 50%, 75%, and 100%) of percentage weight loss regained (weight change from years 1-4 as percentage of first year weight loss). Change in cardiometabolic risk factors after initial weight loss was compared in maintainers and regainers, after controlling for demographics, medications, and baseline and year 1 change in body mass index. The effect was assessed separately in participants with <10% and ≥10% initial weight loss, and women and men. Maintainers exhibited significant improvements to the cardiometabolic risk factors assessed compared with regainers. No weight regain cut point maximized risk difference between maintainers and regainers across risk factors or sex/initial weight loss subgroups. For many risk factors, allowing more regain as part of maintenance (increasing cut point) diminished the cardiometabolic benefit among maintainers. Conclusions Maintaining weight loss was better than regain for all risk factors. No single cut point maximized the risk difference between maintainers and regainers. Maintainers who kept off ≥75% of weight lost had the greatest benefit. These findings emphasize the importance of intervention programs focusing not only on weight loss but weight loss maintenance, given the adverse consequences of the latter. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00017953.