Assessed with child interview questions created by the study team. Questions ask children to respond by indicating which smiley face on a 5 point analog scale best represents how they feel, from 1 (unhappy/not at all) to 5 (very happy/a lot). Acceptability was assessed by asking how much the child liked the intervention, and motivation was assessed by asking the child how motivated they are to eat healthier post-intervention. Greater numbers on each question represent greater acceptability and greater post-intervention motivation, respectively.

Child self-report survey measure. The Self-Efficacy for Healthy Eating and Physical Activity (SE-HEPA) measure was developed by Steele, Bindler, Power, and Daratha (2008) and is based on Motl et al.'s (2000) unidimensional measure of self-efficacy for exercise. Based on Bandura's (1977) social cognitive theory, SE-HEPA was designed to evaluate a children's or adolescents' confidence in their ability to engage in healthy eating (8 items) and physical activity behaviors (8 items). Items are answered on 5 point Likert scales from strongly disagree (1) to strongly agree (5). Scores are summed to create two subscales: self-efficacy for healthy eating, and self-efficacy for physical activity. Possible scores for each subscale range from 8 to 40, with greater scores indicating greater self-efficacy.

The caregiver Readiness to Change Diet and Physical Activity items were adapted from previously used questions and designed to assess caregiver readiness to help their child change physical activity and eating behaviors. Parents self-report their intentions to help their children with healthy habits by answering "Do you intend to find ways to improve the way your child eats?" and "Do you intend to find ways to improve your child's physical activity level?" with responses from 1 ("No, and I'm not intending to make changes"), 2 ("Yes, I intend to make changes in the next 6 months"), 3 ("Yes, I intend to make changes in the next month"), to 4 ("I'm already helping my child improve their [eating/activity]"). Scores range from 1 to 4, with greater scores indicating greater caregiver readiness to help their child change. Items are not aggregated, and each item is analyzed separately.

Behavioral beliefs (attitudes) and intentions toward health eating were measured with items adapted from previous literature based on the Theory of Planned Behavior. Where needed, language was adapted to lower the reading level for child participants. Items were answered on 7 point Likert scales from strongly disagree (1) to strongly agree (7). Scores were summed for child attitudes (beliefs), child intentions, and caregiver intentions, self-reported by children and caregivers pre- and post-intervention. Eight items measured child attitudes towards eating healthy, with total scores ranging from 8 to 56, and greater scores indicating more positive attitudes toward eating healthier.

Six items measured child intentions toward healthy eating, with total scores ranging 6 to 42, and greater scores indicating greater intentions to engage in the behavior.

Four items measured caregiver intentions to help child, with total scores ranging from 4 to 28, and greater scores indicating gre

Parents reported on their child's activity behavior of the previous week with two different items asking parents to report the average number of hours per day the child engaged in screen time and physical activity, on a scale from 1 to 5, with 1 = none; 2 = less than 1 hour per day; 3 = 1 to 2 hours per day; 4 = 3 to 4 hours per day; 5 = more than 4 hours per day.

This is the control condition, which views a short video and online interactive game with psychoeducational material on healthy eating and consideration of future consequences.

This is the intervention condition, which participates in the virtual reality experience; the experience includes psychoeducational material on healthy eating and consideration of future consequences.

Virtual Reality Experience: The virtual reality experience includes psychoeducation content about healthy eating and consideration of future consequences. It includes a game where participants are in a go kart and pick up healthy or unhealthy foods on the road. Participants play in the "present" and in the "future."

Total of all reporting groups

The Usefulness, Satisfaction and Ease of Use Questionnaire was used to measure acceptability, specifically usefulness, ease of use, ease of learning, and satisfaction with an intervention or service. Items were adapted to have the caregivers report on their child's experience of usability. The shortened instrument used in this study (Lund, 2001) contains 19 items, and respondents indicate their agreement with each statement on a scale from 1 (strongly disagree) to 7 (strongly agree). Scores are summed to create an overall score of usability, ranging from 19 to 133, with greater scores indicating greater usability.

Data were reported by the caregivers, who reported for both the child and themselves. Only one score is reported for each child-caregiver dyad.

Degree of Immersion in the virtual environment is assessed by parent self-report with the Presence Questionnaire (Witmer 2005). The Presence Questionnaire is a 24 item questionnaire that assesses involvement, auditory fidelity, adaption/immersion, interface quality, consistency with expectations, and haptic/visual fidelity. Given that sense of touch was not applicable to the present study, this item (23) was not included in the final score. Responses to the items are on a scale from 1 (not at all) to 7 (completely), and responses are summed to create an overall score. Potential scores range from 23 to 161, with greater scores indicating greater self-reported feelings of being immersed in the virtual environment.

Data were collected in Virtual Reality condition only. Data were reported by the caregivers, who reported for both the child and themselves. Only one score is reported for each child-caregiver dyad.

Assessed with child interview questions created by the study team. Questions ask children to respond by indicating which smiley face on a 5 point analog scale best represents how they feel, from 1 (unhappy/not at all) to 5 (very happy/a lot). Acceptability was assessed by asking how much the child liked the intervention, and motivation was assessed by asking the child how motivated they are to eat healthier post-intervention. Greater numbers on each question represent greater acceptability and greater post-intervention motivation, respectively.

Data were reported by the child only. This item was not collected from caregivers.

Child self-report survey measure. The Self-Efficacy for Healthy Eating and Physical Activity (SE-HEPA) measure was developed by Steele, Bindler, Power, and Daratha (2008) and is based on Motl et al.'s (2000) unidimensional measure of self-efficacy for exercise. Based on Bandura's (1977) social cognitive theory, SE-HEPA was designed to evaluate a children's or adolescents' confidence in their ability to engage in healthy eating (8 items) and physical activity behaviors (8 items). Items are answered on 5 point Likert scales from strongly disagree (1) to strongly agree (5). Scores are summed to create two subscales: self-efficacy for healthy eating, and self-efficacy for physical activity. Possible scores for each subscale range from 8 to 40, with greater scores indicating greater self-efficacy.

Data were reported by the child only. These data were not collected from caregivers.

The caregiver Readiness to Change Diet and Physical Activity items were adapted from previously used questions and designed to assess caregiver readiness to help their child change physical activity and eating behaviors. Parents self-report their intentions to help their children with healthy habits by answering "Do you intend to find ways to improve the way your child eats?" and "Do you intend to find ways to improve your child's physical activity level?" with responses from 1 ("No, and I'm not intending to make changes"), 2 ("Yes, I intend to make changes in the next 6 months"), 3 ("Yes, I intend to make changes in the next month"), to 4 ("I'm already helping my child improve their [eating/activity]"). Scores range from 1 to 4, with greater scores indicating greater caregiver readiness to help their child change. Items are not aggregated, and each item is analyzed separately.

Data were reported by the caregivers only. Only one score is reported for each child-caregiver dyad. These measures were not collected from children.

Behavioral beliefs (attitudes) and intentions toward health eating were measured with items adapted from previous literature based on the Theory of Planned Behavior. Where needed, language was adapted to lower the reading level for child participants. Items were answered on 7 point Likert scales from strongly disagree (1) to strongly agree (7). Scores were summed for child attitudes (beliefs), child intentions, and caregiver intentions, self-reported by children and caregivers pre- and post-intervention. Eight items measured child attitudes towards eating healthy, with total scores ranging from 8 to 56, and greater scores indicating more positive attitudes toward eating healthier.

Six items measured child intentions toward healthy eating, with total scores ranging 6 to 42, and greater scores indicating greater intentions to engage in the behavior.

Four items measured caregiver intentions to help child, with total scores ranging from 4 to 28, and greater scores indicating gre

The outcome measures were analyzed separately for children and caregivers. Data below was collected by either the child only or the caregiver only, as indicated in the row title. Different measures were collected for children and caregivers, as indicated in the measure description.

Parents reported on their child's eating behavior of the previous week with three different items asking parents to report the number of servings per week the child ate of fruits, vegetables, and fast foods.

Data were reported by the caregivers, who reported for on the child's behavior. Only one score is reported for each child-caregiver dyad.

Parents reported on their child's eating behavior of the previous week with two different items asking parents to report the number of days per week the child ate breakfast and family dinner.

Data were reported by the caregivers, who reported for on the child's behavior. Only one score is reported for each child-caregiver dyad.

Parents reported on their child's activity behavior of the previous week with two different items asking parents to report the average number of hours per day the child engaged in screen time and physical activity, on a scale from 1 to 5, with 1 = none; 2 = less than 1 hour per day; 3 = 1 to 2 hours per day; 4 = 3 to 4 hours per day; 5 = more than 4 hours per day.

Data were reported by the caregivers, who reported for on the child's behavior. Only one score is reported for each child-caregiver dyad.

This is the intervention condition, which participates in the virtual reality experience; the experience includes psychoeducational material on healthy eating and consideration of future consequences.

Virtual Reality Experience: The virtual reality experience includes psychoeducation content about healthy eating and consideration of future consequences. It includes a game where participants are in a go kart and pick up healthy or unhealthy foods on the road. Participants play in the "present" and in the "future."

This analysis is for the outcome: Change in Self-Efficacy for Healthy Eating. It is an independent samples t test. It is testing the null hypothesis that the mean change in self-efficacy for healthy eating does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance was set at p<0.05.

This analysis is for the outcome: Change in Caregiver Readiness for Physical Activity. It is an independent samples t test. It is testing the null hypothesis that the mean change in caregiver intentions to help child improve physical activity from baseline to two-week follow up does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p< .05.

This analysis is for the outcome: Change in child intentions toward healthy eating. It is an independent samples t test. It is testing the null hypothesis that the mean change in child intentions toward healthy eating from baseline to post-intervention does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p<.05.

This analysis is for the outcome: Change in caregiver intentions toward helping their child engage in healthy eating. It is an independent samples t test. It is testing the null hypothesis that the mean change in caregiver intentions from baseline to post-intervention does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance is set at p<.05.

This analysis is for the outcome: Change in child intake of vegetables. It is an independent samples t test. It is testing the null hypothesis that the mean change in child vegetable servings per week from baseline to two-week follow up does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p<.05.

This analysis is for the outcome: Change in child intake of fast food. It is an independent samples t test. It is testing the null hypothesis that the mean change in child fast food servings per week from baseline to two-week follow up does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p<.05.

This analysis is for the outcome: Change in child intake of family dinners. It is an independent samples t test. It is testing the null hypothesis that the mean change in child family dinners per week from baseline to two-week follow up does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p<.05.

This analysis is for the outcome: Change in child active hours. It is an independent samples t test. It is testing the null hypothesis that the mean change in child active hours per week from baseline to two-week follow up does not differ between conditions.

Degrees of freedom = 25

A priori threshold for statistical significance set at p<.05.