To our knowledge, this study is the first to show that coping self-efficacy, but not autonomous motivation or emotional coping, may be responsible for reducing depressive symptoms following a lifestyle behavior intervention for low-income overweight and obese women with young children. The finding that coping self-efficacy significantly mediated the association between the intervention and depressive symptoms is inconsistent with results from another RCT that showed neither problem-focused coping, problem-solving ability, nor social coping mediated the effect of a problem-solving education intervention on depression among low-income mothers with young children . The contradictory findings might have resulted from differences between the studies in participant demographics and measurement. While the current study included predominately Non-Hispanic White overweight and obese women, the previous study included predominately Hispanic women with all body sizes . The current study measured coping self-efficacy, whereas the prior study measured mastery or the degree that women perceived themselves as being in control of their lives . Even though the current study showed a small effect size (POMP = -2.53%) for coping self-efficacy, it underscored the importance of including coping self-efficacy in intervention studies aimed at alleviating depressive symptoms in low-income overweight and obese women with young children .
The current study demonstrated that the lifestyle behavior intervention alleviated depressive symptoms. This finding is consistent with results of a prior systematic review and meta-analysis of five RCTs conducted with overweight or obese women of reproductive age who participated in lifestyle behavior interventions . Four of the five interventions tested in the RCTs were directed toward improving both PA and diet, and one focused only on increasing PA. However, in contrast to the current study, none of the five interventions had a stress management component. Moreover, none of the RCTs specifically focused on only low-income women with young children; therefore, the findings cannot be generalized to this high-risk group. Only one study was found that included predominately low-income women to test the effect of a lifestyle behavior intervention on reducing depressive symptoms. The culturally-tailored intervention, which was designed to increase PA and improve diet among Latina pregnant or postpartum women, consisted of home visits and group meetings that were conducted during pregnancy and between two and six weeks postpartum. Compared to the control, the intervention group had a significantly greater decrease in depressive symptoms from baseline to late pregnancy; however, from baseline to approximately six weeks postpartum, no between-group differences occurred . Although continued research is needed in this area, the findings suggest that interventions addressing only PA and/or diet may not be adequate for achieving this outcome in low-income women with young children.
The positive intervention effect on coping self-efficacy supports results from both a mind-body intervention for human immunodeficiency virus (HIV)-infected individuals  and a self-directed cognitive behavioral therapy and mindfulness-based stress reduction intervention for adults . Similar to the current study, these two studies included practical problem-solving strategies (e.g., time management; realistic goal setting) to overcome daily challenges in order to manage stress [26, 43]. Researchers aiming to increase coping self-efficacy may want to consider including practical problem-solving strategies in future studies.
Consistent with a prior study of young women , this study found that increasing coping self-efficacy reduced depressive symptoms. The findings support Bandura’s  Social Cognitive Theory propositions that high coping self-efficacy can mitigate depressive symptoms. Some examples of strategies to increase coping self-efficacy are modeling appropriate behaviors, providing feedback on progress to promote mastery, using verbal persuasion through encouraging statements , helping individuals to identify strengths, recognizing existing skills, and encouraging small steps to change .
The finding that this study’s intervention increased emotional coping was consistent with results from a RCT that included family caregivers of individuals with dementia . Both the current and prior studies focused on teaching participants relaxation exercises (e.g., breathing deeply, counting to 10, and taking a walk)  and emotion-focused coping strategies (e.g., thinking positively and seeking emotional support). Therefore, relaxation exercises and emotion-focused coping strategies may warrant consideration to increase emotional coping.
Results from the current study showing that emotional coping had no influence on depressive symptoms were consistent with those from a mindfulness-based intervention to reduce overeating in low- to middle-income overweight pregnant women . The similar findings suggest that emotion-focused coping strategies may be insufficient for reducing depressive symptoms in overweight and obese women who have a low-income.
The lack of an intervention effect on autonomous motivation in this study contrasted with results from a PA intervention for overweight and obese women . The inconsistent findings may have occurred due to measurement issues. To measure autonomous motivation, the current study included the Treatment Self-Regulation Questionnaire , whereas the latter study used the behavior-specific Exercise Self-Regulation Questionnaire . Regardless, this study’s lack of an intervention effect on autonomous motivation was not completely surprising because of low attendance in the peer support group teleconferences (average 2.6 [SD = 3.4] of 10 teleconferences; 12.4% completed all 10). Despite efforts to schedule teleconferences at times convenient for each group’s members, women’s busy schedules, sudden time conflicts, or disconnected phones prevented them from attending some sessions . Thus, the inability to receive the expected dose of motivational interviewing may have hampered the intervention effect on autonomous motivation.
The positive association between autonomous motivation and depressive symptoms in this study is counter to Self-Determination Theory and evidence indicating that autonomous motivation contributes to enhancing positive mental health outcomes [48–50]. However, one prior study did show that greater intrinsic motivation was positively related to depressive symptoms among athletes playing team sports, the majority of whom were female . One potential explanation for the positive association is that individuals with more depressive symptoms are likely to experience greater psychosocial demands, which may result in increased autonomous motivation to meet the demands . This information suggests that that the association between autonomous motivation and depression may be more complex than anticipated , warranting further investigation.
Strengths and limitations
The study had strengths and limitations. Strengths included its sample of socioeconomically disadvantaged overweight and obese women with young children, a group notably underrepresented in RCTs [53–54]. Because the current study only included overweight and obese mothers of young children in the Midwestern U.S., the findings may not be generalizable to healthy weight mothers and women in other geographical regions. The depressive symptoms data were obtained via self-report instead of clinician interview (or electronic health record), the latter of which is the gold standard for diagnosing a mental health condition . However, the CES-D is the most commonly used measure for depressive symptoms, and conducing clinician interviews to collect data on depressive symptoms is not practical in community settings. Also, this study was a secondary analysis, which might have been underpowered to detect some significant findings.