Development and testing of a web-based intuitive eating intervention for weight gain prevention among mid-age women
Introduction Women aged 40-50 years are at risk of weight gain and weight-related health conditions. Restricting food intake (‘dieting’) often results in short-term weight loss, but not long-term weight management. Eating in accordance with hunger and satiety signals (‘intuitive eating’) and the ability to be fully aware in the present moment and take action guided by values (‘psychological flexibility’) are associated with lower body mass index (kg/m2) and greater weight stability. Intuitive eating and psychological flexibility skills when taught in a group setting are effective at preventing weight gain. It is unknown whether teaching skills online is also effective. Objectives This thesis aimed to develop and test a novel web-based Acceptance and Commitment Therapy (ACT)-focused intuitive eating intervention (‘Mind, Body, Food’) for mid-age New Zealand women. The research involved two distinct phases. Phase I investigated the relationship between psychological flexibility and three-year weight change among mid-age New Zealand women and evaluated the appropriateness of teaching psychological flexibility skills for long-term weight management. Intervention prototypes were developed and pre-tested among overweight mid-aged New Zealand women. Phase II investigated the acceptability of the web-based intervention prototype among the target audience. Phase II also examined mid-age New Zealand women’s use of the Internet and online weight management tools and interest in the proposed intervention. Methods In 2009, a sample of 2500 randomly selected New Zealand women aged 40-50 years, was invited to participate in a prospective study. Linear and logistic regressions were used to investigate associations between baseline psychological flexibility and weight change and weight stability over three years among 1025 women, with specific food and eating habits hypothesised as mediators. Intuitive eating and ACT topics were identified in a literature review, as were effective features of web-based behaviour change interventions. A prototype of the intervention was pre-tested (n=28) with 40-50 year old women with a BMI >27 kg/m2. Feedback informed modifications to layout, features, and content. The intervention was translated to a web-based prototype that underwent further usability testing. The acceptability and preliminary effectiveness of the intervention was tested in a single-arm prospective feasibility study (n=40). Responses were tabulated from a five-year follow-up survey of mid-age New Zealand women’s use of the Internet and interest in the proposed intervention. Results Psychological inflexibility was significantly associated with three-year weight instability (p=0.030), justifying inclusion of psychological flexibility skills in the intervention. Pre-testing showed the intervention layout to be simple and easy to navigate. The content’s emphasis on empowerment, self-acceptance and gradual behaviour change through small, achievable steps was appealing. In the 14-week feasibility study, most women found the intervention useful and made it easy to learn intuitive eating skills. Self-reported intuitive eating increased significantly (p<0.001) and BMI remained unchanged from pre-intervention to post-intervention (p=0.463) and remained unchanged at three-month follow-up (p=0.931). In a nationwide survey, overweight women showed higher usage of web-based weight management tools and more interest in using the proposed weight management intervention compared to women whose BMI was less than 27 kg/m2. Conclusions The novel ACT-based intuitive eating intervention for weight gain prevention developed in this thesis is an appealing tool for mid-age New Zealand women. Further modifications are necessary to improve usability and adherence. Preliminary results support the intervention’s effectiveness, but a randomised controlled trial with adequate long-term follow-up is required.
Advisor: Horwath, Caroline; Gray, Andrew
Degree Name: Doctor of Philosophy
Degree Discipline: Preventive and Social Medicine
Publisher: University of Otago
Keywords: web-based; intervention; intuitive eating; Acceptance and Commitment Therapy; women; mid-age; psychological flexibility; weight gain prevention
Research Type: Thesis