IMPORTANCE: Weight loss may be difficult for young women with obesity to achieve due to competing priorities (caring for children and/or full-time work), limiting their ability to engage in weight loss interventions. Older or postmenopausal women may also face challenges to weight loss such as caring responsibilities and menopause. Menopausal status may reflect differences in weight loss. OBJECTIVE: This study compared changes in weight, fat mass, and lean mass in premenopausal versus postmenopausal women in dietary weight loss trials. EVIDENCE REVIEW: We reviewed publications from January 2000 to June 2020 evaluating a weight loss intervention with a dietary component, with or without exercise, and reporting weight loss of premenopausal and postmenopausal women. Where available, data on mean change from baseline for weight, fat mass, and lean mass of premenopausal and postmenopausal groups were entered into Review Manger for meta-analyses. Differences between menopausal groups were compared in subgroups of studies for intervention characteristics (diet-only vs diet and exercise; dietary modification vs meal replacement; < 24 wks vs ≥24 wks duration). FINDINGS: Seven publications (10 interventions, n = 791) were included; three single-arm trials, two randomized controlled trials, and two comparative effectiveness trials. In meta-analyses, there were no statistically significant differences between premenopausal and postmenopausal women (shown as premenopausal minus postmenopausal) for change in weight (0.58 [95% confidence interval -0.12 to 1.28] kg, n = 7 interventions), fat mass (0.73 [-0.25 to 1.70] kg, n = 6 interventions), or lean mass (-0.5 6[-1.48 to 0.36] kg, n = 4 interventions). However, a statistically significant subgroup difference was observed for fat mass change between menopausal groups (premenopausal minus postmenopausal) when comparing diet-only (1.28 [0.23 to 2.33] kg, n = 4 interventions) versus diet and exercise interventions (-0.09 [-0.51 to 0.32]kg, n = 2 interventions). No differences were shown in any other subgroups. CONCLUSIONS AND RELEVANCE: This review provides some evidence to suggest weight loss interventions may not need to be tailored to women's menopausal status. However, given the small number of studies, short intervention duration in most publications (≤ 6 mo) and unclear retention rates in premenopausal versus postmenopausal groups of some publications, menopausal group differences should be examined in existing and future trials where the appropriate data have been collected.