Obesity can severely reduce quality and longevity of life and there is an urgent need to help people lose weight and maintain weight loss long term. Digital behaviour change interventions targeting diet and physical activity have the potential for public health gain; however, these interventions are often not adequately tailored to the participants. The aim of this study is to develop and test a digital intervention to help people make sustainable changes to diet and physical activity, and consequently their weight. This study is a hybrid trial that will evaluate the effectiveness, cost-effectiveness and implementation of the Choosing Health program among overweight/obese adults. This study is a two-group randomised controlled trial (RCT) with within person assessment. Participants (N=285) will be randomly assigned to either the Choosing Health digital intervention or a control group. For intervention participants, Ecological Momentary Assessment (EMA) will be used to identify behavioural determinants for each individual in order to tailor evidence-based behaviour change techniques and intervention content. Control group will receive non-tailored factual weight loss advice. Primary outcome is mean difference in weight loss between groups at 6 months, in kilograms. Key outcomes will be measured at baseline, 3-, 6- and 12 months. Data will be analysed using multilevel modelling and time series analysis. This is the first weight loss intervention applying individualised digital tailoring based on continuous assessment of individual's psychological determinants of behaviour measured over time. The Choosing Health will offer insight into factors associated with success in making sustained changes to weight, and secondary outcomes, such as diet and physical activity.
Behavioural science offers theory-driven and evidence-based behaviour change techniques that can support people in losing weight and maintaining it long term. These techniques have not yet been assessed in within-person studies that not only examine aggregated between-group effects (e.g., intervention versus control comparisons) but also determine personal trajectories of weight loss and maintenance and tailor accordingly to the strongest predictors of outcomes. The aim of the proposed study is to develop and test a digital intervention that uses Ecological Momentary Assessment (EMA) and tailors the evidence-based behaviour change techniques that are based on theory to the strongest predictors of outcomes (based on EMA responses collected over time). This study will determine the effectiveness and cost-effectiveness of the proposed intervention through the Randomised Controlled Trial (EMA tailored intervention versus control), with within person component embedded in the trial. Study hypothesis is that participants in the EMA tailored intervention group will lose significantly more weight than participants in the control group from baseline to 6 months (post program comparison - primary outcome) and at 12 months (maintenance effects assessment - secondary outcome). This is a two-group intervention trial adopting a randomised controlled design. It is a hybrid trial assessing intervention effectiveness, cost-effectiveness and implementation. This study has within person component embedded in the design and intervention group will answer EMA questions during the initial 3 months of the study and will receive tailored intervention at month 3 combined with additional EMA. There are two phases of the 6-month intervention (I) observational EMA phase and (II) active intervention phase. The proposed intervention is delivered online through emails and text messages and based on the EMA responses in phase I, it is tailored in phase II. The intervention will have a non-automatic component, meaning trained facilitators will answer participants' queries and provide additional resources if and when needed to improve the engagement with the intervention. The study meets CONSORT criteria for RCTs and study ethical approval was obtained from SWPS University of Social Sciences and Humanities, Wroclaw, Poland (approval number 03/P/12/2019).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
285
The intervention consists of information materials provided at baseline in a form of eBook or a physical book depending on participants preferences. The book includes the rationale for the intervention, basic information on healthy eating and behaviour change and tables allowing self-monitoring of weight, physical activity and eating (i.e., brief food diary). The book is non-tailored and it has weekly tasks for the participants to complete during 26 weeks (initial 6 months) to support their weight loss. The intervention group will also receive a series of daily text messages and weekly email messages supporting their weight loss and promoting weight loss maintenance. In phase I (month 0-3), the messages and emails will be generic and factual; in the phase II of the intervention, participants will receive text messages and emails tailored to the strongest predictors of outcomes identified in phase I.
The control consists of information materials provided at baseline in a form of eBook or a physical book depending on participants preferences. The book includes the rationale for the intervention and basic information on healthy eating and physical activity. The control group will also receive monthly email messages with generic and factual information.
SWPS University
Wroclaw, Silesian Voivodeship, Poland
Weight
Mean difference in weight loss between groups at 6 months, in kilograms
Time frame: Change from baseline to 6 months
Weight
Objective measures of weight in kilograms
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Height
Objective measures of height in centimetres
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
BMI
Weight and height will be combined to report BMI in kg/m\^2
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Body fat %
Objective measures of body fat %
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Systolic and diastolic blood pressure
Objective measures of systolic and diastolic blood pressure measured in units of millimeters of mercury (mmHg)
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Diet
Measured with the Dietary Instrument for Nutrition Education (fatty foods, fruit and vegetable, and sugary food consumption). High scores are indicative of high consumption. Higher scores for fruit and vegetable mean a better outcome (0-3 scale; 1 item) and higher scores for fatty foods (0-24; 8 items on 0-3 scale) and sugary food (0-9; 3 items on 0-3 scale) mean a worse outcome. The minimum values are 0 and the maximum values are specified above in brackets.
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Alcohol
Measured with the Audit C; scale 0-12, high scores are indicative of high consumption.
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Physical activity (self-reported) and sitting time
Measured with the International Physical Activity Questionnaire short version, the minimum value is 0 (no activity), higher scores mean a better outcome. All activity will be converted to minutes before calculating MET minutes (total score). In each category a maximum of 21 hours of activity are permitted a week (3 hours X 7 days). To calculate MET minutes a week the MET value given (walking = 3.3, moderate activity = 4, vigorous activity = 8) will be multiplied by the minutes the activity was carried out and again by the number of days that that activity was undertaken. To get total MET minutes of physical activity a week the MET minutes achieved in each category (walking, moderate activity and vigorous activity) will be added.
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Sleep duration and quality
Measured with the Pittsburgh Sleep Quality Index. In scoring the Pittsburgh Sleep Quality Index, seven component scores are derived, each scored 0 (no difficulty) to 3 (severe difficulty). The component scores are summed to produce a global score (range 0 to 21). Higher scores indicate worse sleep quality.
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Health related quality of life
Measured with the EQ-5D-5 L (this is the unabbreviated scale title), the scale has five domains each scored on 1-5 scale; min 5 maximum 25 for all domains combined) higher scores mean a worse outcome and visual analogue scale is the second part of the questionnaire, asking to mark health status on the day of the interview on a 20 cm vertical scale with end points of 0 and 100. There are notes at the both ends of the scale that the bottom rate (0) corresponds to " the worst health you can imagine", and the highest rate (100) corresponds to "the best health you can imagine".
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Number of adverse effects
report of any adverse effects that may occur during the intervention
Time frame: Through study completion, an average of 1 year
Self-reported measures of intentions
Theory-derived psychological construct measured with 2 items addressing intentions (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a better outcome (higher intentions).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of motivation
Theory-derived psychological construct measured with 2 items addressing motivation (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a better outcome (higher motivation).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of self-efficacy
Theory-derived psychological construct measured with 2 items addressing self-efficacy (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a better outcome (higher self-efficacy).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of attitudes
Theory-derived psychological construct measured with 2 items addressing attitudes (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a better outcome (higher attitudes).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of action planning
Theory-derived psychological construct measured with 8 items addressing action planning (1-5 scale), the minimum and maximum values for the scale are 8-40, and higher scores mean a better outcome (better action planning).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of coping planning
Theory-derived psychological construct measured with 6 items addressing action planning (1-5 scale), the minimum and maximum values for the scale are 6-30, and higher scores mean a better outcome (better coping planning).
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of goal facilitation
Theory-derived psychological construct measured with 2 items addressing goal facilitation (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a better outcome (better goal facilitation)
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of goal conflict
Theory-derived psychological construct measured with 2 items addressing goal conflict (1-5 scale), the minimum and maximum values for the scale are 2-10, and higher scores mean a worse outcome (higher goal conflict)
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of habit strength for physical activity
Theory-derived psychological construct measured with h self-report behavioural automaticity index for physical activity, 4 items (1-5 scale); the minimum and maximum values for the scale are 4-20, and higher scores mean a better outcome (habit strength)
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
Self-reported measures of habit strength for healthy eating
Theory-derived psychological construct measured with self-report behavioural automaticity index for healthy eating, 4 items (1-5 scale); the minimum and maximum values for the scale are 4-20, and higher scores mean a better outcome (habit strength)
Time frame: baseline (Time 0), 3 months (Time 1), 6 months (Time 2) and 12 months (Time 3)
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