People with excess weight (EW) are characterized by high impulsivity, high levels of craving for high-calorie foods, deficits in inhibitory control, and maladaptive decision-making. The proposed intervention seeks to target these issues. Thus, the present study aims to determine the effectiveness of combining inhibitory control training with usual treatment (diet and physical exercise) in treating people with EW to produce cognitive, behavioral and anthropometric changes. Participants will be randomly allocated to one of two groups: 1) the experimental group that would receive active inhibitory control training and (2) the active control group that will receive placebo inhibitory control training. Both groups will receive individualized diet and physical exercise guidelines. Training requires to inhibit responding to certain foods presented during computerized tasks. Using a food Go/No-Go paradigm, individuals are asked to press a button when a Go cue is presented next to an image and to refrain from pressing a button when a No-Go cue (e.g., a bold frame) is presented. In the experimental group, pictures of healthy and unhealthy foods are always paired with the Go and the No-Go signal, respectively whereas in the control group healthy and unhealthy foods are paired 50% of the time with the Go and 50% with the No-Go signal. It is hypothesized that the experimental intervention would be effective improving (i) Body Mass Index (BMI), (ii) food craving, (iii) anthropometric measures (waist circumference and waist-to-hip and waist-to-height ratios), (iv) eating and physical exercise behaviors (decreased caloric intake and increased frequency and time of physical activity), (v) emotional symptoms and emotional eating (depression, anxiety, emotional regulation, emotional eating, reward-related eating, non-homeostatic eating), and (vi) cognitive abilities (motor and cognitive inhibition, delay of gratification, impulsivity, working memory, cognitive flexibility and decision making).
1. HYPOTHESIS: Inhibitory control training with the food Go/NoGo paradigm will be effective in treating people with EW. Thus, the active intervention, compared to the placebo, will achieve: (i) decreased BMI, (ii) decreased craving, (iii) improved anthropometric measures (waist circumference and waist-to-hip and waist-to-height ratios), (iv) improved eating and exercise behaviors (decreased caloric intake increased frequency and time of physical activity), (v) improved emotional symptoms and emotional eating (depression, anxiety, emotional regulation, emotional eating, reward-related eating, non-homeostatic eating), (vi) improved cognitive abilities (motor and cognitive inhibition, delay of gratification, impulsivity, working memory, cognitive flexibility and decision making). GENERAL OBJECTIVE: To determine the effectiveness of inhibitory control training for the treatment of people with EW (improvements in BMI, craving, anthropometric measures, food and physical exercise behaviours, emotional symptoms and emotional eating, and cognitive measures). 2. METHODOLOGY 2.1. Design: Randomized controlled trial of parallel groups. The sample size calculation was performed with the G\*Power 3.1 tool. To do so, it will be relied on the only study to date that applied food Go/NoGo training (4 sessions in one week) on a median effect size for reducing BMI post-treatment (Cohen's d = 0.57) and at 6-month follow-up (Cohen's d = 0.48). Thus, considering a median effect size for conducting ANOVAs (f= 0.25), the minimum recommended N to reach a power of 0.80, assuming an alpha level of 0.05 with two groups and three repeated measures, was 44 participants, 22 per group. Nevertheless, a conservative approach will be adopted and decided to increase groups to 27 participants. The participants (N=54) will be randomly allocated to two groups: (i) experimental group (active inhibitory control training); n=27 and (ii) active control group (placebo inhibitory control training); n=27). 2.3. Interventions Pre-treatment sessions: information, dietary plus physical guidelines (all groups): First, all participants will participate in a group briefing informational session about the procedure and rationale of the study that will last about an hour. Also, informative videos and brochures will be provided. There will be two 90-minute sessions afterwards given by a nutritionist and personal trainer respectively to provide individualized diet and physical exercise instructions to all participants. Cognitive interventions (both groups): Duration: 2 weeks in which participants should train from monday to friday for 10 minutes with the active or the placebo version of the Food Trainer App (FoodT) with their smart phones. 2.4. Outcome measures: change in Body Mass Index (BMI) will be the main outcome measure. Secondary outcomes will be changes in food craving, anthropometric measures, eating and physical activity behaviours, emotional symptoms and emotional eating, and cognitive measures. Screening and descriptive measured will include a sociodemographic questionnaire, depression and anxiety questionnaires, motivation and questionnaire on Eating and Weight Patterns-5. 3. PROCEDURE The whole study will be delivered online. Inclusion and exclusion criteria will be checked through the data collected in a questionnaire of sociodemographic and clinical variables. Further, psychopathology exclusion criteria will be tested with three questionnaires to measure depression, anxiety, and stress symptoms as well as binge eating and bulimia (BDI, DASS-21 and QEWP-5), and a short clinical interview by phone and/or information requested by email in those cases where there are doubts about any of the aspects collected through the online instruments. All candidates who meet the criteria will attend an information meeting about the project in which participants will receive written and oral information and will be asked for their informed consent. Then, participants will be randomly assigned to groups before the pre-treatment assessment sessions. Both groups of the study (experimental and active control) will complete pre and post assessments, as well as the 3-month follow-up (see below). What will differentiate the groups will be, therefore, the treatment: active vs. placebo inhibitory control training. If at the end of the project the active training has proven to be effective, the control group will be offered the possibility to carry out the active training. All sessions will be developed in groups of 4-6 people. There will be at least 5 groups of intervention sessions (27 participants) and 5 groups for the placebo condition (27 participants). The program will comprise 6 weeks including three assessments (pre, post and 3-month follow-up), two FoodT training weeks, as well as the information and nutrition and exercise sessions. Assessment sessions will last about 2 hours each while the inhibitory control training will last 10 minutes per day. 1. Informative session (session 1; week 1): For the participants to understand the foundation of the intervention information about the aims, basis of the project and the procedure of the research will be given. Participants will be provided written informed consent as well. At the end of this session, participants will be asked for their informed written consent. 2. Pre-treatment assessment (session 2; week 2): All participants will complete the following instruments to assess the main and secondary outcomes, and the exploratory and economic measures: WCST, Food Go/NoGo, IGT, Stroop, Food DD, N-Back, FCQ-S-r, CFA, IPAQ, DASS-21, BDI-II, PEMS, RED, DEBQ, PSRSQ, ERQ, UPPS-P, SF-36, SOCRATES 00, QEWP-5, sociodemographic questionnaire, another one about used health resources, stigma and previous treatments questions. 3. Nutrition and exercise sessions (session 3; week 3): Participants will receive information on healthy nutritional (Ph.D. Nutritionist) and physical exercise (Ph.D. Sports Science professional) habits. In addition, participants will receive individualized diet and physical exercise guidelines, and participants will be able to consult any doubts to both professionals through WhatsApp groups. 4. Training sessions (sessions 4 to 14, weeks 4 and 5): A daily reminder will be sent by WhatsApp to the participants' phone to train from Monday to Friday during 10 minutes for two weeks. The FoodT app will be used to pair high-calorie meals with the no-go cue. Images can appear on the left, right or center of the screen, and should be tapped or not depending on whether the image has a green or red circle around them. Participants earn points for correct tapping responses and lose points for incorrect tapping responses and must respond as quickly and accurately as possible. The placebo FoodT has images of objects rather than food. 5. Post-treatment assessment (session 15; week 6): To evaluate the effectiveness of the interventions, BMI and the following instruments will be administered to obtain the main and secondary outcomes: FCQ-T/S-r, WCST, Food Go/NoGo, IGT, Stroop, Food DD, N-Back, CFA, IPAQ, DASS-21, BDI-II, PEMS, RED, DEBQ, PSRSQ, ERQ, UPPS-P, SF-36, and a questionnaire about used health resources. 6. Follow-up (session 16; week 18): Follow-up at 3 months after the intervention will include the following measures: FCQ-T/S-r, WCST, Food Go/NoGo, IGT, Stroop, Food DD, N-Back, FCQ-S-r, CFA, IPAQ, DASS-21, BDI-II, PEMS, RED, DEBQ, PSRSQ, ERQ, UPPS-P, SF-36 and a questionnaire about used health resources. Anthropometric measures will be repeated as well. Every month after the end of the treatment, participants will be contacted by email and mobile message to maintain adherence.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
54
Computerized cognitive training. Participants will perform the task of the FoodT app for 10 minutes during two weeks (taking advantage of time of maximum brain potentiation, Rossi et al., 2009). Images of food and non-food appear on the left, right or centre of the smart phone screen and participants must touch it (or not, depending on the cue) with their index finger as quickly as possible. Participants earn points for correct tap responses and lose points for incorrect tap responses. If the image has a green border around it, participants must tap the image and win 1 point. But if the image has a red border around it, participants must inhibit the tapping response, or lose 1 point. Participants must respond as quickly and accurately as possible. Pictures of healthy and unhealthy foods are always paired with the Go and the No-Go signal, respectively. Non-food images are paired 50% of the time with the Go and the No-Go signal
Computerized cognitive training. Participants will perform the task of the FoodT app for 10 minutes during two weeks (taking advantage of time of maximum brain potentiation, Rossi et al., 2009). Images appear on the left, right or centre of the smart phone screen and participants must touch it (or not, depending on the cue) with their index finger as quickly as possible. Participants earn points for correct tap responses and lose points for incorrect tap responses. If the image has a green border around it, participants must tap the image and win 1 point. But if the image has a red border around it, participants must inhibit the tapping response, or lose 1 point. Participants must respond as quickly and accurately as possible. Here, three separate categories of non-food items (stationery, flowers and clothing) would be Go signal (associated with green 100%), No-Go signal (associated with red 100%) and control (50% red 50% green) respectively.
Mind, Brain and Behavior Research Center at University of Granada (CIMCYC)
Granada, Spain
RECRUITINGBody Mass Index (BMI). Mean change from baseline at post-intervention
BMI is a measure of body fat based on height and weight. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m\^2. Height and weight will be obtained with a pharmacy digital weight.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Food Craving. Mean change from baseline at post-intervention
Change in food Craving. Food Craving Questionnaire State-reduced (FCQ-S-r)consists of 15 items to be scored on a 5-point scale ranging from strongly disagree to strongly agree. A higher score indicates higher state of craving at the time of the assessment
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Waist circumference (WC). Mean change from baseline at post-intervention
To take these measurements at home, participants should ask someone for help and follow our instructions. WC will be measured in cm with a tape around the waist, just above the navel.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)]
Waist-to-hip ratio (WHR). Mean change from baseline at post-intervention
To take these measurements at home, participants should ask someone for help and follow our instructions. WHR results from WC divided by the hip circumference in cm (tape placed at the maximum prominence of the buttocks).
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)]
Waist-to-height ratio (WHtR). Mean change from baseline at post-intervention
To take these measurements at home, participants should ask someone for help and follow our instructions. WHtR results from WC divided by the height measured standing with heels close together and trunk erect.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)]
Eating behaviour. Mean change from baseline at post-intervention
Diet information during the last year (pre-treatment), two last weeks (post-treatment) and 3 last months (follow-up) will be collected through a 52-item Food frequency questionnaire (CFA). Participants must record quantities of all the foods and drinks consumed during those periods. Data are transformed into total calories and calories from fats, carbohydrates, and sugars
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)]
Physical activity behaviour. Mean change from baseline at post-intervention
International Physical Activity Questionnaire (IPAQ; www.ipaq.ki.se): is a questionnaire with 7 questions on physical activity during the last week, as well as walking and sitting time.It evaluates physical activity related to work, activity at home and free time determines the degrees of activity based on the metabolic equivalents (MET) consumed.Higher scores indicate greater physical activity
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)]
Anxiety and Stress. Mean change from baseline at post-intervention
The Depression Anxiety Stress Scale-21 (DASS-21) will be used, taking into account scores on the stress and anxiety subscales. The scores for both subscales range from 0 to 21, a higher score indicating higher anxiety or stress.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Depression symptoms. Mean change from baseline at post-intervention
Beck Depression Inventory will be administered to test depression symptoms.The scores range from 0 to 63 points. The higher the score, the greater the severity of depressive symptoms.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Non homeostatic eating. Mean change from baseline at post-intervention
Dutch Eating Behaviour Questionnaire (DEBQ) will be administered to assess restrictive eating behaviours related to external cues and emotional states. Higher scores in each subscale reflect higher level of restrained, emotional, and external eating, respectively.The DEBQ uses a 5-point Likert scale, ranging from never (1) to very often (5). The average score is calculated for each subscale by adding scores obtained from individual items and dividing them by the number of items included in a subscale (mean range: 1-5).
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Reward-related eating. Mean change from baseline at post-intervention
Reward-Based Eating Scale (RED) is a 13 items questionnaire that evaluates worries about foods, losing intake control and absence of satiety. Higher scores reflect higher reward-based eating drive.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Emotional eating. Mean change from baseline at post-intervention
Coping subscale of the Palatable Eating Motives Scale (PEMS) will be used to evaluate the intentionality for eating palatable foods to face negative emotions. The coping subscale includes items that are scored on a 5-point Likert-type scale, the total range being from 5 to 25 points. Low scores indicate that the person rarely resorts to the consumption of pleasant foods as a strategy to cope with negative emotions or stressful situations. High scores suggest that the person frequently uses palatable food as a strategy to cope with stress or negative emotions, which may be related to unhealthy eating habits or emotional eating patterns.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Emotion Regulation Strategies. Mean change from baseline at post-intervention
The Emotion Questionnaire (ERQ) consists of 10 items to examine cognitive reappraisal and expressive suppression strategies. In cognitive reappraisal the highest score (42) is associated with better emotional outcomes while in expressive suppression the highest score (28) is linked to poorer well-being. Each item is rated on a Likert scale from strongly disagree (1) to strongly agree (7).
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Motor inhibition. Mean change from baseline at post-intervention
Motor inhibition will be assessed using FoodT. In the FoodT app reaction time for the high-calorie and low-calorie foods paired with the go and the no-go signal. The average response time for go and no-go items will be calculated according to the type of images (appetizing and healthy foods), and commission errors will be recorded.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Cognitive inhibition. Mean change from baseline at post-intervention
Using a Stroop task with food, the interference of food-related words on task performance can be measured as an assessment of cognitive inhibition.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Delay of gratification. Mean change from baseline at post-intervention
Score on the Food Delay Discounting will be used to measure the sensitivity to immediate rewards vs higher value rewards delayed. The participant's choices are recorded for each trial. Each trial varies in terms of the amount of reward and the amount of time to wait. To model the decisions, a hyperbolic discounting function is generally used.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Inhibition and activation systems. Mean change from baseline at post-intervention
This will be assessed using the Punishment Sensitivity and Reward Sensitivity Questionnaire (PSRSQ) of 48 items. Responses in the scale are in a "yes/no" format. Higher punishment sensitivity scores are associated with lower number of punishable errors while higher reward sensitivity punctuations are linked to higher number of passive avoidance errors.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Self-reported impulsivity. Mean change from baseline at post-intervention
Self-reported impulsivity will be measured with Impulsive behaviour scale (UPPS-P). It consists of 20 items scored on a four point Likert scale, ranging from strongly agree (1) to strongly disagree (4). Higher scores mean worse outcome in impulsivity, while lower scores are related to better self-control and regulation
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Working Memory. Mean change from baseline at post-intervention
Working Memory will be assessed using N-back Task score based on accuracy and reaction times. Higher accuracy scores indicate stronger working memory and attention, while faster reaction times are linked to quicker processing speed and decision-making.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Cognitive flexibility. Mean change from baseline at post-intervention
Wisconsin Card Sorting Test will be administered to measure shift strategy in response to changing contingencies. There are128 trials where more correct responses, fewer perseverative and non perseverative errors, and more completed categories (max 6) are related to better performance.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
Decision making. Mean change from baseline at post-intervention
Iowa Gambling Task will be used to assess decision-making using money rewards.
Time frame: Pre-treatment assessment (week 2), post-treatment assessment (week 6) and follow-up (week 18)
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