Although the prevalence of overweight and obesity has remained stable in recent years, weight management remains a challenge for a large sector of the population. Particularly during young adulthood, women are at increased risk for excess weight gain. Rather than focusing on the treatment of excess body weight through energy restriction, which has proven to be ineffective in facilitating long-term weight loss, an alternative and more robust approach may be to emphasize the improvement of health and lifestyle behaviors to aid in prevention of weight gain over time. A 1-year randomized controlled trial of weight gain prevention was conducted in a sample of premenopausal women to determine the effects of a weight gain prevention intervention that included nutrition education on body weight (BW) change and other health outcomes over one year. This trial also aimed to compare the delivery of nutrition education by a registered dietitian to a counselor.
Women (n=87) were randomized to a control group (CON; n=29) or weight gain prevention intervention delivered by a registered dietitian (RDG; n=29) or counselor (CSG; n=29). Eighty-one women (meanSD, age: 31.4±8.1 y; BW: 76.1±19.0 kg; body mass index: 27.9±6.8 kg/m2) completed baseline testing and were included in intention-to-treat analyses (CON=26; RDG=26; CSG=29). During the intervention period, women in the RDG and CSG groups attended 16 weekly and 8 monthly 1-hour nutrition education sessions. Anthropometric, blood pressure, dietary intake, physical activity, biochemical markers of health, eating behaviors, health perceptions and mediators of behavior change data were collected and evaluated at baseline and every three months thereafter. All data were analyzed using the Statistical Package for the Social Sciences (version 22.0, 2013).
The weight gain prevention intervention was successful in preventing weight gain over one year; however, BW change between the RDG, CSG and CON was not significantly different, and 62% of the original sample successfully prevented weight gain. Few differences were observed by group or over time using intention-to-treat analyses. Body fat percentage was significantly lower in the RDG compared to the CSG and CON at all time points (P0.01), resting heart rate (P>0.01), systolic and diastolic blood pressure (P>0.01), macronutrient intake (P>0.01), food group servings (P>0.01), total energy expenditure (P>0.01) or biochemical markers of health (P>0.01). There were no significant effects of time for any anthropometric measurements (P>0.01), resting heart rate (P>0.01), diastolic blood pressure (P>0.01), dietary intake (P>0.01), total energy expenditure (P>0.01) or biochemical markers of health (all P>0.01). A cross-sectional examination of eating behaviors and grit, a non-cognitive personality trait, revealed that disinhibition was a significant predictor of BW and body mass index (BMI). Significant associations between grit and cognitive eating restraint (CER; r=0.23, P<0.05), disinhibition (r=–0.47, P<0.01), hunger (r=–0.19, P=0.05), BW (r=–0.24, P<0.05) and BMI (r=–0.23, P<0.05) were found. Over time, baseline grit did not predict BW change, but it was negatively associated with BW and BMI at month 12 (r=-0.25, P<0.05; r=-0.23, P<0.05). Disinhibition was the only predictor of month 12 BW, and women who successfully prevented weight gain had significantly lower levels of disinhibition at baseline (P<0.05) and significantly increased CER over the intervention (P<0.05).
Though the current weight gain prevention found no significant effects of nutrition education on weight gain prevention over time, a large proportion of individuals were able to maintain BW during the study interval. Further, disinhibition and changes in CER were related to successful weight gain prevention. Future interventions that address additional indicators of health and explore strategies to increase CER and manage disinhibition in order to facilitate prevention of weight gain over time are needed.
