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. Author manuscript; available in PMC: 2021 Aug 1.
Published in final edited form as: Appetite. 2020 Apr 10;151:104700. doi: 10.1016/j.appet.2020.104700

Mediators of Intervention Effects on Dietary Fat Intake in Low-Income Overweight or Obese Women with Young Children

Mei-Wei Chang 1, Alai Tan 1, Jiying Ling 2, Duane T Wegener 3, Lorraine B Robbins 2
PMCID: PMC7305970  NIHMSID: NIHMS1585972  PMID: 32283187

Abstract

Purpose.

We investigated whether autonomous motivation and self-efficacy might mediate the association between a lifestyle behavior intervention and dietary fat intake in low-income overweight or obese women with young children.

Methods.

Participants were randomized to an intervention or comparison group. Intervention participants received a 16-week intervention aimed to prevent weight gain through promotion of stress management, healthy eating and physical activity. During the intervention phase, participants viewed a designated video lesson at home and dialed in a peer support group teleconference every week (weeks 1–4) then every other week (weeks 5–16). Potential mediation effects were analyzed using sequential mixed-effects linear models and path analysis.

Results.

The intervention led to increased autonomous motivation (β = 0.34, standard error [SE] = 0.15, P = 0.005), which subsequently increased self-efficacy (β = 0.18, SE = 0.35, P < 0.001), and higher levels of self-efficacy were associated with decreased dietary fat intake (β = −0.22, SE = 0.28, P < 0.001). In other words, autonomous motivation and self-efficacy mediated the association between the lifestyle behavior intervention and dietary fat intake.

Conclusion.

To decrease dietary fat intake for low-income overweight or obese women with young children, strategies, such as those promoting peer encouragement, may be warranted in interventions to enhance autonomous motivation and/or practical skills for increasing self-efficacy.

INTRODUCTION

Encouraging obese adults to decrease dietary fat intake has been a focus for the majority of weight loss intervention studies (Ma et al., 2017) and a recommendation for prevention of weight gain studies (Cornier, Marshall, Hill, Maahs, & Eckel, 2011). A recent meta-analysis of weight loss intervention studies showed that a diet low in fat was associated with weight loss when compared to usual diet (or maintaining usual diet) (Tobias et al., 2015). Another recent meta-analysis demonstrated that a diet low in fat, especially saturated fat, decreased risk of premature mortality by 18% (Ma et al., 2017). One of the groups that may potentially benefit from a lifestyle intervention with emphasis on reducing dietary fat intake is low-income overweight or obese women with young children because they are likely to eat high-fat foods (George, Milani, Hanss-Nuss, & Freeland-Graves, 2005).

Most low-income overweight or obese postpartum women experience significant postpartum weight retention, retain ≥ 10 lbs from pregnancy (Endres et al., 2015), and such weight retention often leads to life-long obesity (Rooney & Schauberger, 2002). Significant weight gain while of child-bearing age increases the risk for developing obesity-related conditions including type 2 diabetes, cardiovascular disease (Zheng et al., 2017), and cancer (Keum et al., 2015). Also, maternal obesity is a determinant of offspring health during childhood and later adult life (Godfrey et al., 2017; Lindsay, Sussner, Kim, & Gortmaker, 2006). Therefore, helping low-income overweight or obese women with young children lose weight is important to promote healthier outcomes of mothers. Unfortunately, current successful weight loss programs are costly and require high intensity treatment, for example, frequently attending in-person meetings and prescribing caloric restriction (Diabetes Prevention Program Research, 2002), which may not be feasible for the target audience due to multiple responsibilities associated with caring for young children and lack of transportation. However, these women may benefit from low-intensity lifestyle intervention programs aimed at prevention of further weight gain. Such programs have shown potential in promoting energy-balance related behaviors, for example, reducing dietary fat intake and body mass index, BMI (Kremers et al., 2010).

We conducted a community-based randomized controlled lifestyle intervention to help members of the target population prevent weight gain through promotion of healthy eating, physical activity, and stress management (Chang, Nitzke, Brown, & Resnicow, 2014). In a recent article, we described the results of the intervention for dietary intake: the intervention significantly improved dietary fat intake immediately after the 16-week intervention (Chang, Brown, & Nitzke, 2017a). In the current article, we focused on a secondary analysis examining whether autonomous motivation and self-efficacy might mediate effects of the intervention to reduce dietary fat intake. That is we examined whether the intervention (the independent variable or predictor) indirectly influenced the outcome of dietary fat intake. More specifically, we expected that being assigned to the intervention (vs. comparison group) would affect the level of participants’ autonomous motivation, and autonomous motivation would influence perceptions of self-efficacy for healthy eating, which would in turn influence the primary outcome of dietary fat intake. This examination focused on mediating variables in that autonomous motivation and self-efficacy were examined as possible variables at least partly responsible for carrying the impact of the intervention (through the mediating variables) to the outcome of dietary fat intake.

Many studies have investigated theory-based psychosocial predictors of dietary change, such as autonomous motivation and self-efficacy, even treating them as potential mediators, or mechanisms that help to explain effects of behavioral interventions. Autonomous motivation, defined as motivation to adopt and sustain behaviors (for example, eating foods low in fat) that are consistent with personal values (for example, being healthy), is a key concept of Self-Determination Theory (Deci & Ryan, 2000). This theory of human motivation clearly identifies autonomy as a human need that, when supported, facilitates autonomous self-regulation (Ng et al., 2012), thereby promoting positive behavior change (Deci & Ryan, 2000).

Prior lifestyle behavior studies have reported mixed results of autonomous motivation as a mediator for fruit and vegetable intake in middle-aged adults regardless of their body size. Specifically, two intervention studies did not find that autonomous motivation mediated the intervention effects on fruit and vegetable intake (Campbell et al., 2008; Fuemmeler et al., 2006). Another intervention study with two intervention arms, culturally targeted materials vs. culturally targeted materials plus motivational interviewing, reported that autonomous motivation was a significant mediator for fruit and vegetable intake only when the intervention included motivational interviewing (Shaikh, Vinokur, Yaroch, Williams, & Resnicow, 2011). Thus, although some evidence supports a potential role for autonomous motivation when a lifestyle intervention involves motivational interviewing, additional data would be helpful in verifying such effects on dietary fat intake and extending those effects to low-income overweight or obese women with young children.

Another key construct in Self-Determination Theory is that of competence, or seeking to experience mastery (Deci & Ryan, 2000). That experience of mastery is directly related to another common psychological construct, that of self-efficacy. Self-efficacy, defined as one’s confidence in effectively executing a behavior in various situations (Bandura, 1997), is a key concept of Social Cognitive Theory. Self-efficacy is crucial for positive behavior change, because one would be unlikely to undertake a new behavior if one lacks confidence that the new behavior will be effective (Bandura, 2004). Results of a recent systematic review and meta-analysis (Teixeira et al., 2015) and several randomized controlled intervention studies (Campbell et al., 2008; Fuemmeler et al., 2006; Partridge, McGeechan, Bauman, Phongsavan, & Allman-Farinelli, 2017; Schneider et al., 2016; Shaikh et al., 2011) have consistently identified self-efficacy as a potential mediator for adult shifts in dietary intake in general and for shifts in fruit and vegetable intake in particular. Also, self-efficacy has served as a plausible mediator for the association between an intervention and sugary beverage intake in obese pregnant women during the second but not the third trimester (van Poppel et al., 2019). Dietary intervention studies of low-income adults have included a measure of self-efficacy, but no analysis of mediation, and reported positive intervention effects on fruit and vegetable intake in women with young children (Langenberg et al., 2000) and Latinos (Ko, Rodriguez, Yoon, Ravindran, & Copeland, 2016) and on dietary fat intake in British adults (Steptoe, Perkins-Porras, Rink, Hilton, & Cappuccio, 2004). Therefore, though there are some indications that self-efficacy for new dietary behaviors might mediate effects of interventions on changes in dietary fat intake, there is little direct evidence for the role of self-efficacy as a mediator in influences on dietary intake behavior of overweight or obese low-income women with young children.

Study Objective and Hypothesis

Understanding potential mechanisms to influence dietary fat intake is critical for increasing the effectiveness of interventions to reduce dietary fat intake in low-income overweight or obese women with young children. This secondary data analysis used data from T1 (baseline) and T2 (immediately after the 16-week intervention) of a community-based lifestyle behavior intervention to investigate whether autonomous motivation and self-efficacy might mediate intervention effects on dietary fat intake in the target population. It was hypothesized that autonomous motivation and self-efficacy can mediate changes in dietary fat intake.

MATERIALS and METHODS

Participants and recruitment

A detailed description of recruitment and study criteria have been published elsewhere (Chang, Nitzke, Brown, & Resnicow, 2014; Chang, Nitzke, Brown, Egan, Bendekgey, Buist, 2017) Briefly, participants were recruited from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Michigan. WIC, a federally funded program, serves low-income pregnant, postpartum and breastfeeding women and children aged 0–5 years old throughout the U.S. (Thorn et al., 2018). To enroll in WIC, one must have an annual household income ≤ 185% of the federal poverty line. Recruitment took place between September 2012 and January 2015. The study-trained peer recruiters invited women to be screened while they waited for their WIC appointments. Participants were non-pregnant, between 18 and 39 years old, non-Hispanic Black or White, and between 6 weeks and 4.5 years postpartum and had a BMI (calculated using measured height and weight) between 25.0 and 39.9 kg/m.2 Eligible women signed a written consent form before participation. The study procedure was approved by the Institutional Review Boards of Michigan State University and Michigan Department of Health and Human Services.

Intervention

Participants were randomized to the intervention or comparison group (2:1 ratio). The intervention had two components: watching culturally sensitive video lessons in DVD format at home and dialing into peer support group teleconferences. The video lessons were completely unscripted and culturally sensitive to the target audience because the lessons included four overweight or obese women with young children enrolled in WIC (hereafter, featured mothers) and their testimonials. They wore casual clothing during the filming at their home, local grocery stores, and neighborhoods. They demonstrated healthy eating and food preparation using foods that were commonly eaten or prepared by the target audience. They also provided testimonials on strategies used to overcome common barriers (for example, unable to say no to others resulting in lack of time for oneself) to make positive behavior changes (Chang, Nitzke, Brown, & Resnicow, 2014). The intervention covered three topics: stress management (four lessons, weeks 1–4), healthy eating (five lessons, weeks 5–14), and physical activity (one lesson, weeks 15–16). During the 16-week intervention, intervention participants viewed ten culturally sensitive video lessons: one designated video lesson weekly (weeks 1–4), then every other week (weeks 5–16). They also dialed into ten peer support group teleconferences weekly (weeks 1–4) followed by every other week (weeks 5–16). Each culturally sensitive video was about 20 minutes in length. The peer support group teleconferences (30 minutes per teleconference) were led by trained moderators who were peer educators or WIC dietitians and who applied motivational interviewing techniques, effective strategies to boost autonomous motivation (Shaikh et al., 2011). To increase autonomous motivation, the videos included featured mothers similar to the target audience demonstrating positive behavioral changes while providing rationales for the change. They also testified that they were engaging in behaviors that were consistent with their personal values. For example, “I read the food label because it is important to me and consistent with my personal values, such as preventing weight gain.” During the peer support group teleconference, the trained moderators elicited and acknowledged the participants’ perspective and/or emotion before making suggestions. They also helped identify relevant behaviors related to participants’ personal values by asking, for example, how consistent eating ice cream frequently would be with their personal value of prevention of weight gain. To increase participants’ self-efficacy, the featured mothers, for example, showed simple and practical ways to make small and gradual changes in each of the key areas: stress management, healthy eating, and physical activity. They also demonstrated ways to overcome barriers or problem solve to facilitate success of making positive changes. During the support group teleconference, the trained moderator, for example, reframed participants’ past failures as lessons learned that could lead to future success. The moderators also helped participants develop plans for making positive behavior changes based on the participants’ skills and experiences.

Measures

Participants provided demographic information using a pencil-and-paper survey while they waited for their appointments at our collaborating WIC offices. Autonomous motivation, self-efficacy, and dietary fat intake data were collected through phone interviews. Trained interviewers, who received weekly written feedback on their phone interviews and attended monthly booster training, conducted all of the interviews. While the trained interviewers conducted the phone interview, they simultaneously entered data into our study data collecting system. A total of 338 women completed both T1 and T2 phone interviews.

Demographics.

The demographic information collected included each participant’s birth date, race, education, and employment status. Birth dates were used to calculate age of study participants.

Autonomous motivation for healthful eating (hereafter referred to as autonomous motivation).

Autonomous motivation for healthful eating was measured using the Treatment Self-Regulation Questionnaire (six items) with good construct validity. The internal reliability indexed through the Cronbach alpha (α) was 0.92. (Pelletier, Tuson, & Haddad, 1997). Participants were asked why they ate healthier for the last three months. For example, “the reason I eat healthier is because I want to take responsibility for my own health.” There were seven response categories ranging from 1 (not at all true) to 7 (very true). The overall autonomous motivation composite was the mean of the six-item responses, with a higher score indicating higher autonomous motivation.

Self-efficacy for healthful eating (hereafter referred to as self-efficacy).

A previously developed eight-item survey with good construct validity and reliability, α = 0.82 (Chang, Nitzke, Brown, Baumann, & Oakley, 2003) was used to measure self-efficacy. Participants were asked to report their confidence in healthy eating in a variety of situations in the past three months. For example, “I can stick to a low-fat diet on a regular basis when angry.” There were four response categories ranging from 1 (usually or always) to 4 (rarely or never). The overall self-efficacy composite was the mean of the eight-item responses, with a higher score indicating higher self-efficacy.

Dietary fat intakes.

A 17-item Rapid Food Screener with reported moderate predictive validity (Spearman correlation = 0.69 for fat intake) was used to measure the frequency of dietary fat intake in the previous three months (Block, Gillespie, Rosenbaum, & Jenson, 2000). There were five response categories: 0 = 1 time per month or less, 1 = 2–3 times per month, 2 = 1–2 times per week, 3 = 3–4 times per week, and 4 = 5 or more times per week. The overall dietary fat intake was the mean of the 17 items, which ranged between 0 and 4. A higher score indicated greater dietary fat intake.

Statistical Analysis

Descriptive statistics were conducted to summarize the sample demographics. Bivariate tests (T-test and Chi-Square statistic) were used to compare the sample demographics between the intervention and comparison groups. Mixed-effects linear models were performed to compare the group differences (intervention vs. comparison) in self-efficacy, autonomous motivation, and dietary fat intake across time (T2 vs. T1).

Next, mixed-effects linear models were used to sequentially examine: 1) the unadjusted intervention effects on dietary fat intake (Model 1, independent variables included group [intervention or comparison], time [T1 or T2], and group by time interaction); 2) intervention effects on dietary fat intake after adjusting for race and employment status (Model 2 – added race and employment status to Model 1); and 3) intervention effects on dietary fat intake after adjusting for race, employment status, autonomous motivation and self-efficacy (Model 3 – added autonomous motivation and self-efficacy to Model 2). Race and employment status were added as covariates in Models 2 and 3 because there were significant group differences in these two demographics. Autonomous motivation and self-efficacy were entered as time-varying covariates in Model 3. All three models included subject-specific random intercepts to adjust for the within-subject clustering from repeated measures.

Lastly, we conducted path analysis to examine the potential mediating effects of changes of autonomous motivation and self-efficacy from baseline in the path from intervention to change of dietary fat intake. We started with a full path model based on our theoretical framework. That is, the intervention was designed to increase both autonomous motivation and self-efficacy for healthy eating. By enhancing engagement with the videos, autonomous motivation could further enhance perceptions of self-efficacy, and both autonomous motivation and self-efficacy could potentially impact dietary fat intake. After examining the full model, we derived a reduced final model based on the estimated path coefficients. Model fit was assessed using Chi-square goodness of fit statistics, the comparative fit index (CFI), Tucker-Lewis index (TLI), and root mean squared error of approximation (RMSEA). We used STATA 4.2 for the path analysis and SAS 9.4 for all other statistical analyses.

RESULTS.

Participants in the intervention group (N = 212) and comparison group (N = 126) were similar in age (29.2 ± 4.9 vs. 29.6 ± 4.9, P = 0.48) and education (27.7% vs. 33.9% with high school or less education, P = 0.23). Compared to the comparison group, the intervention group had higher percentages of White (84.5% vs. 76.4%, P = 0.06) and were unemployed (59.2% vs. 47.2%, P = 0.03).

Table 1 shows changes in autonomous motivation, self-efficacy, and dietary fat intake over time (T2 vs. T1), stratified by intervention and comparison groups. Compared to the comparison group, the intervention group had a significantly greater increase in autonomous motivation (0.46 ± 1.07 vs. 0.13 ± 1.05, P = 0.005) and self-efficacy (0.29 ± 0.55 vs. 0.13 ± 0.56, P = 0.01), and a greater decrease in dietary fat intake (−0.29 ± 0.46 vs. −0.18 ± 0.39, P = 0.03).

Table 1.

Autonomous motivation, self-efficacy and fat intake by time and groups (N = 338)

Variable Mean (SD)
T1 (Baseline) T2 (Immediately after the 16-week intervention) Change from T1 to T2
Intervention Comparison P-value Intervention Comparison P-value Intervention Comparison P-value
Autonomous Motivation 5.63 (1.23) 5.74 (1.25) 0.432 6.10 (0.98) 5.87 (1.20) 0.073 0.46 (1.07) 0.13 (1.05) 0.005
Self-Efficacy 2.67 (0.55) 2.65 (0.57) 0.774 2.95 (0.49) 2.78 (0.54) 0.002 0.29 (0.55) 0.13 (0.56) 0.010
Fat Intake 1.27 (0.49) 1.25 (0.51) 0.692 0.98 (0.45) 1.06 (0.45) 0.107 −0.29 (0.46) −0.18 (0.39) 0.026
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Autonomous motivation ranged from 1 to 7; the higher score, the higher autonomous motivation.

Self-efficacy ranged from 1 to 4; the higher score, the higher self-efficacy.

Fat intake ranged from 0 to 4; the higher score, the greater dietary fat intake.

Table 2 presents the estimates from the sequential mixed-effects linear regression models. Intervention effects on dietary fat intake were indicated by the group by time interaction in the models. Results from Models 1 and 2 suggested that: (1) there were significant intervention effects on reducing dietary fat intake (coefficient [β] = −0.10, standard error [SE] = 0.05, P = 0.03) (Model 1); (2) there were no changes in the estimates of intervention effect after adjusting for race and employment status (Model 2); and (3) although the intervention and comparison groups differed in race and employment status, these two demographics were not significantly associated with dietary fat intake after adjusting for other independent variables. After adding self-efficacy and autonomous motivation as time-varying covariates in Model 3, the intervention effects were no longer significant with a half reduction in coefficient estimate (β = −0.05, SE = 0.04, P = 0.25) and both autonomous motivation (β = −0.03, SE=0.02, P = 0.033) and self-efficacy (β = −0.24, SE=0.05, P < 0.001) were significantly associated with dietary fat intake, suggesting that autonomous motivation and self-efficacy can mediate the intervention effects on dietary fat intake.

Table 2.

Sequential mixed-effects linear regression models on factors related to dietary fat intake

Variable Model 1 Model 2 Model 3
Coefficient (SE) P-value Coefficient (SE) P-value Coefficient (SE) P-value
Group (Intervention vs. comparison) 0.02 (0.05) 0.678 0.03 (0.05) 0.633 0.03 (0.05) 0.576
Time (T2 vs. T1) −0.19 (0.04) <0.001 −0.19 (0.04) <0.001 −0.15 (0.04) <0.001
Group*Time (Intervention at T2 vs. other) −0.10 (0.05) 0.032 −0.10 (0.05) 0.032 −0.05 (0.05) 0.254
Race (Black vs. White) 0.07 (0.06) 0.218 0.11 (0.06) 0.051
Employment (Employed vs. unemployed) −0.02 (0.05) 0.660 −0.03 (0.04) 0.523
Autonomous motivation −0.03 (0.02) 0.033
Self-efficacy −0.24 (0.03) <0.001
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Note. SE=standard error

The results from path analysis (Figure 1) further confirmed the potential mediating roles of changes in autonomous motivation and self-efficacy from baseline in the path from intervention to change of dietary fat intake. The full model (Figure 1A) based on our original theoretical framework suggested that there were no significant direct intervention effects on dietary fat intake when controlling for the potential mediators of change in autonomous motivation or change in self-efficacy (β= −0.06, SE = 0.07, P=0.18). Also, when controlling for potential influences of autonomous motivation, influences of the intervention on changes in self-efficacy did not reach significance (β = 0.11, SE = 0.09, P = 0.07). Finally, when controlling for influences of changes in self-efficacy, the relation between autonomous motivation and dietary fat intake was also no longer significant (β = −0.03, SE = 0.06, P = 0.25). Therefore, these paths were deleted to derive the final reduced model (Figure 1B). Like the initial full model, the final path model suggested that the intervention significantly increased autonomous motivation (β = 0.34, SE = 0.15, P = 0.005), that changes in autonomous motivation subsequently increased self-efficacy (β = 0.18, SE = 0.35, P < 0.001), and that changes in self-efficacy decreased dietary fat intake (β = −0.22, SE = 0.28, P < 0.001). The final model had a good fit with Chi-square statistic of 6.75 (P = 0.08), CFI of 0.95, TLI of 0.91, and RMSEA of 0.06.

Figure 1.

Figure 1.

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Path analysis

DISCUSSION

To the best of our knowledge, this is the first lifestyle intervention study that examined autonomous motivation and self-efficacy as potential mediators for intervention effects on changes in dietary fat intake among low-income overweight or obese women with young children. Findings from this study support our hypothesis that autonomous motivation and self-efficacy can mediate changes in dietary fat intake in the target population. In other words, autonomous motivation and self-efficacy form plausible psychological mechanisms explaining the significantly decreased dietary fat intake due to the intervention. This finding suggests the importance of including both autonomous motivation and self-efficacy into lifestyle intervention studies aimed to improve dietary fat intake. While autonomous motivation plays a key role in adopting and maintaining a healthful diet, self-efficacy is critical for overcoming barriers in the initial stage of adoption and is the first step to increase motivation for positive changes (Teixeira et al., 2015). It is important to note that, in past research, self-efficacy has been a promising mediator in the short-term dietary behavior change in overweight or obese adults but may not be sufficient for long-term change. To sustain the positive behavior change, autonomous motivation might play a crucial role (Teixeira et al., 2015).

Our study found that autonomous motivation played a key role in mediating the intervention effects on dietary fat intake. This finding is consistent with one previous intervention study aimed to increase fruit and vegetable intake in middle-aged African American adults (Shaikh et al., 2011). However, our finding is contradictory to two previous intervention studies aimed to increase fruit and vegetable intake in adults (Campbell et al., 2008) and middle-aged African Americans (Fuemmeler et al., 2006). In Campbell et al’s study, the authors also reported that autonomous motivation was not a mediator of intervention effects on fruit and vegetable intake in women enrolled in WIC (Campbell et al., 2008). Our and Campbell’s findings suggest that autonomous motivation might play a different role for different types of dietary intake or that autonomous motivation primarily plays a role when the intervention includes specific strategies to increase autonomous motivation (see intervention section above for description of strategies).

Our finding that autonomous motivation influenced dietary fat intake through self-efficacy is consistent with prior cross-sectional studies of physical activity (McNeill, Wyrwich, Brownson, Clark, & Kreuter, 2006; Sweet, Fortier, Strachan, & Blanchard, 2012; Thogersen-Ntoumani & Ntoumanis, 2006). More intervention studies are needed to confirm our findings. Nevertheless, researchers conducting lifestyle behavior intervention studies may consider including effective strategies to improve autonomous motivation to reduce dietary fat intake in low-income overweight or obese women with young children. One example to increase autonomous motivation is asking the target audience to identify personal values that are important to their current life (e.g., being a good role model for young children, be healthier), and then guiding the target audience to assess the congruence between their current eating behaviors and their selected personal values.

Consistent with prior studies reporting self-efficacy as a mediator of intervention effects on fruit and vegetable intake (Campbell et al., 2008; Fuemmeler et al., 2006; Shaikh, Vinokur, Yaroch, Williams, & Resnicow, 2011) and sugar-sweetened beverage consumption (van Poppel et al., 2019), results of the present study demonstrated that self-efficacy mediated the association between intervention and dietary fat intake. In line with previous cross-sectional studies showing a negative relation between self-efficacy and dietary fat intake (Horton, Timmerman, & Brown, 2018; Steptoe et al., 2004), the current study found that increased self-efficacy can result in decreased dietary fat intake in low-income women. A recent longitudinal study showed that poverty led to low self-efficacy, which is associated with poor health outcomes. It might be especially important, therefore, to examine ways to increase self-efficacy in low-income populations. Self-efficacy is a key means of promoting health behavior change (for example, eating foods low in fat) leading to better health outcomes (Callander & Schofield, 2016), and the current research suggests that a culturally sensitive lifestyle intervention may be successful in improving health outcomes of low-income women, in part, because of shifts in self-efficacy. Therefore, future intervention studies aimed to decrease dietary fat intake of the target population may consider emphasizing self-efficacy for healthy eating. Examples to boost self-efficacy in the target population include providing specific strategies on ‘how’ to eat healthier or specific steps to make small and gradual changes instead of simply giving an instruction on what the individuals should or need to do. Also, it is important to help the target audience identify or realize personal strengths or successes in the past in the past, even if they were small, through asking open-ended questions, as was done in the teleconferences in the current intervention. Finally, it is critical to provide concrete examples of goal setting as we have observed that this population has challenges in setting goals for making positive behavioral changes (Chang, Brown, & Nitzke, 2017b).

The study has a few limitations. First, it is a secondary data analysis. As a secondary analysis of an existing dataset, the study was not specifically designed for power associated with the current mediational tests. The study’s findings are also limited to be generalized to low-income overweight or obese women who are non-Hispanic Black or White. It is unclear whether similar effects could be found with other populations. Also, there were significant group differences in race and employment status at baseline, though race and employment status were not significantly associated with dietary fat intake and they were included as covariates in the analysis. Lastly, all study outcomes were measured by self-report scales. Therefore, recall bias may exist. However, currently there is no valid objective measurement for dietary fat intake that does not involve some form of self-reported dietary intake.

CONCLUSIONS.

Results of the present study showed that autonomous motivation and self-efficacy served as significant mediators between our lifestyle behavior intervention and dietary fat intake. Future lifestyle intervention studies for low-income overweight or obese women with young children could consider including features focused on autonomous motivation and self-efficacy for healthful eating. Doing so might effectively decrease dietary fat intake.

Acknowledgement

The lifestyle behavior intervention project was supported by the National Institutes of Health (Grant Number R18-DK-083934)

Footnotes

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Declarations of interest: none

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