Abstract Objectives As individuals age, they become more susceptible to developing weight-related obesity comorbidities–which makes weight loss and weight maintenance key issues in older age groups. Prior research on the efficacy of weight loss programs across age groups has yielded inconsistent results. The Bright Line Eating (BLE) program, which follows a food addiction model that emphasizes abstinence from added sugars and processed flours, has been shown to be effective for weight loss and weight maintenance. This study builds on that research to assess age-related differences in the efficacy of the BLE program. Methods Participants in this study (n = 4509; 93.9% white; 95.6% female; 29.6% overweight, 58.2% obese at baseline) attended an 8-week BLE Boot Camp program and completed pre- and post-program surveys that measured demographic characteristics, anthropometrics, and psychosocial factors. We used two-way ANOVA to assess the effect of age on % weight loss from baseline (%WL) while accounting for race, gender, and program adherence. Logistic regression was used to estimate the effect of age on improvement in quality of life, energy level, and life satisfaction. Results Participants experienced 6.5%WL (SD = 5.2) with no significant difference across age groups (F = 1.5, P = 0.15). After completing the BLE Boot Camp program, 54.3% reported improved quality of life, 46.6% reported higher energy levels, and 60.4% described increased life satisfaction. Percent weight loss was associated with improvements in all of psychosocial factors that we examined (z = 13.8, P < .000; z = 13.5, P < .000; z = 12.4, P < .000). Older study participants were more likely than younger to see an increase in energy level (z = 2.8, P = 0.01). Conclusions This evaluation of the BLE Boot Camp program demonstrated its success across all adult age groups. These results are particularly encouraging, given the need for feasible and scalable weight loss interventions that have been shown to be effective across all demographic groups. Funding Sources None to report.