Understanding the psychological dimension of eating behavior in overweight children and adolescents is of clinical importance, as it could facilitate the effective tailoring of treatment to patient characteristics. This study demonstrated that, in the short to medium term, a structured and prescriptive dietary intervention approach is a suitable option for obese adolescents with clinical features of insulin resistance. This approach led a reduction in dysfunctional eating behaviors, particularly external and emotional eating and lead to modest weight loss.
Both external and emotional eating reduced significantly during the intensive dietary intervention phase (0 to 3 months) and levels were maintained to 6 months with continued weight loss. This finding is in agreement with those from a recent systematic review of adult studies . One possible explanation is that the structured meal plan helped participants control the tendency to overeat to achieve the initial weight loss during the first 3 months, and facilitated other factors relevant to weight to support ongoing weight loss.
Different intervention approaches may lead to different treatment effects. People with high levels of external and emotional eating consume food not just because they are hungry but because they are controlled by external food cues or emotions . A previous study of personality traits in obese adults demonstrated that external and emotional eating are associated with impulsiveness and lower self-control . In addition, a study in 7 to 12 year olds has shown that emotional eating is positively associated with longer screen time which may pose a higher risk for mindless eating and the development of excess weight gain . One important finding of the current study is that a prescriptive dietary intervention approach led to a reduction in emotional eating over 6 months. A structured and prescriptive meal plan with detailed instruction on types and portion size of food, as well as when to eat, may help to promote self-control skills, and therefore reduce the tendency for external and emotional eating. In our study, this speculation is supported by parents reporting that their child felt more in control of their eating habit and was happy or content during the study period. Therefore, a structured and prescriptive meal plan may be used as a coping strategy for external eaters to confront external food cues.
A reduction in dietary restraint score was associated with weight loss in the medium term (0 to 6 months). However, we are not able to draw any firm conclusions as to whether dietary restraint is a symptom, a cause or an effect of overweight. From both a theoretical and clinical point of view dietary restraint is to some extent required in order for weight control to occur. Nevertheless, according to the Theory of Restrained Eating, dietary restraint is a maladaptive behavior in obese people and is related to eating pathology via vicious cycles of eating, weight and shape concerns [9, 26, 27]. Excessive restraint may have a counterproductive effect and eventually lead to weight gain [4, 10]. Consistent with the literature , we found that dietary restraint was prevalent among obese adolescents, as 60% of participants reported dietary restraint either frequently or always at baseline, with this remaining unchanged over the 6 months. This finding suggests that implementation of a prescriptive, low energy meal plan did not elicit further adverse effects on dietary restraint. However, additional studies are required to explore effective strategies for rectifying the dietary restraint traits in obese children and adolescents.
A high protein diet is considered to have a greater effect on satiety [28–30]. We had expected that the moderate carbohydrate, increased protein diet would elicit different effects on eating behaviors compared to the high carbohydrate and low fat diet. Nevertheless, there were no significant differences in the change in eating behaviors or diet acceptability between diet groups at any time point. Therefore, we speculate that the observed changes in external eating and emotional eating are due to the intervention approach rather than the macronutrient content of the diets. This preliminary finding should be confirmed with further research.
To our knowledge, this is the first study to report the effects of obesity treatment on the psychological dimensions of eating behaviors in adolescents and their relation to weight loss. There are several limitations in this study. Firstly, the questionnaire used in this study has been validated in pre-adolescents, whereas the participants of RESIST trial were 10 to 17 year olds. EPI-C was the instrument with best face validity for assessing the psychological dimensions of eating behaviors in children when the RESIST trial commenced. Of note, the internal consistency for the present sample was 0.8 for all the psychological dimensions of eating behaviors. Secondly, possible bias of self-reporting of eating behavior cannot be completely ruled out. Future studies may include parent reports of their child’s eating behavior as supplementary information. Thirdly, the possible effect on any outcomes of providing a proportion of food to the families in the first 3 months was not evaluated. In addition, as all participants in this study were prescribed metformin, the possible confounding effect of this medication on appetite control cannot be excluded. Furthermore, this paper is a secondary data analysis of an RCT examining the effects of two diets on the insulin sensitivity of obese adolescents with clinical features of insulin resistance. We did not have a control group who received no intervention and thus the findings should be interpreted with caution. Finally, as this study was conducted among obese adolescents with prediabetes and/or clinical features of insulin resistance, further research is needed to validate the effectiveness of the prescriptive dietary intervention approach compared with conventional lifestyle interventions in the general obese population.
In conclusion, in the short to medium term, a prescriptive dietary intervention approach has no adverse effect on the psychological dimensions of eating behaviors and was well-accepted by parents of obese adolescents with clinical features of insulin resistance. Due to the complex nature of obesity, different individuals may need different treatment approaches to achieve their weight loss goal. This study demonstrates that a prescriptive dietary intervention approach may be used as a coping strategy for external eaters. Further dietary intervention approaches for obese children with different eating styles, and the long-term effectiveness of prescriptive dietary interventions, need to be explored.