Weight-loss intervention using implementation intentions and mental imagery: a randomised control trial study protocol

Abstract

BackgroundOverweight and obesity are major health problems worldwide. This protocol describes the HEALTHI (Healthy Eating and Active LifesTyle Health Intervention) Program, a 12-week randomised-controlled weight-loss intervention that adopts two theory-based intervention techniques, mental imagery and implementation intentions, a behaviour-change technique based on planning that have been shown to be effective in promoting health-behaviour change in previous research. The effectiveness of goal-reminder text messages to augment intervention effects will also be tested. The trial will determine the effects of a brief, low cost, theory-based weight-loss intervention to improve dietary intake and physical activity behaviour and facilitate weight-loss in overweight and obese individuals.Methods/DesignOverweight or obese participants will be randomly allocated to one of three conditions: (1) a psycho-education plus an implementation intentions and mental imagery condition; (2) a psycho-education plus an implementation intentions and mental imagery condition with text messages; or (3) a psycho-education control condition. The intervention will be delivered via video presentation to increase the intervention’s applicability in multiple contexts and keep costs low. We hypothesise that the intervention conditions will lead to statistically-significant changes in the primary and secondary outcome variables measured at 6 and 12 weeks post-intervention relative to the psycho-education control condition after controlling for baseline values. The primary outcome variable will be body weight and secondary outcome variables will be biomedical (body mass, body fat percentage, muscle mass, waist-hip circumference ratio, systolic and diastolic blood pressure, low-density lipoprotein, high-density lipoprotein, total cholesterol, triglycerides, blood glucose and insulin levels), psychological (quality of life, motivation, risk perception, outcome expectancy, intention, action self-efficacy, maintenance self-efficacy, goal setting and planning), and behavioural (self-reported diet intake, and physical activity involvement) measures. We also expect the intervention condition augmented with text messages to lead to statistically significant differences in the primary and secondary outcome variables at the follow up periods after controlling for baseline values.DiscussionThe planned trial will test the effectiveness of the theory-based HEALTHI program intervention to reduce weight and salient psychological, biomedical, and behavioural outcomes in overweight and obese adults. The study has been designed to maximise applicability to real world settings and could be integrated into existing weight management practices.Trial registrationACTRN: ACTRN12613001274763. Registration date 19/11/2013.

Garden-Based Integrated Intervention for Improving Children’s Eating Behavior for Vegetables

“…The outcome expectation is the recognition of the consequences of a behavior, and the greater advantages and fewer disadvantages they associate with it, the more people perform that behavior [37,46]. As the visualization of the outcome is based on a positive image related to goal achievement and success, this could serve as motivation for achieving the behavioral objective [55]. In this study, children had hands-on experience in the garden for growing vegetables so that they could increase outcome expectancies for vegetable.…”

Predicting Physical Activity‐Related Outcomes in Overweight and Obese Adults: A Health Action Process Approach

“…In addition, participants allocated to one of the intervention conditions also received goal reminder text messages to increase adherence to the planning and imagery exercises. The full protocol for the intervention is provided in a separate article outlining the specific details of the intervention content, study design, and method (Hattar, Hagger, & Pal, ). While participants in the three conditions differed in the behaviour change techniques used, no intervention effects were found within the data used for the current study.…”

“… The protocol article by Hattar and colleagues () provides a comprehensive list of intervention inclusion and exclusion criteria. …”

Effect of the depletion of self-control strength on the self-regulation of the nutritional process in obese individuals

“…According to theoretical background and many experiments dealing with the problem in question, the depletion of resources should decrease the level of self-control required for other behaviors, among them the control of dietary habits [13,15,16]. However, previously reported experiments on the self-control of nutrition revealed that a high level of motivation, involvement in the process of losing weight along with active learning and practicing proper dietary habits are reflected by the development of intrinsic, resistant to depletion self-control, which protects against the risks related to caloric food [18,19,20,21]. Therefore, we assumed that verifying the effect of resource depletion is important in such an experimental group, and our findings do not necessarily have to be consistent with the results of previous studies dealing with the problem in question [13,15,16].…”