Abstract
Men in the United States have an exceptionally high prevalence of overweight and obesity, i.e., 71.3%, and
42% of men are currently attempting weight loss. However, men are dramatically underrepresented in weight
loss programs. Men find conventional weight loss program (i.e., group-based, education and counseling-
orientated, dietary/calorie-focused) unappealing because they involve receiving counseling, focus on replacing
“masculine” foods (e.g., meat) with “feminine” ones (e.g., salad), and provide minimal personalization or
autonomy. As such, attempts have been made to increase recruitment and appeal through targeted
recruitment and adaptations to standard weight loss programs. However, these efforts have been
disappointing. Mobile applications (mHealth apps) have attractive features, but have low male enrollment and
poor efficacy as conventionally delivered. A gamified mHealth program offers the possibility of engaging men
and enhancing efficacy given that (1) video gaming is highly appealing to men; (2) gamification features (e.g.,
digital rewards for attaining “streaks” and milestones, competition) are known enhance enjoyment and
motivation and facilitate desired behaviors; and (3) “neurotraining” video games featuring repetitive action
mechanics, adaptive difficulty, and feedback can train inhibitory control, a basic brain capacity to inhibit
intrinsically-generated approach responses that is strongly linked to body mass and the consumption of high-
calorie foods. Inhibitory control training (ICT) games have been successful at reducing consumption of targeted
foods/beverages and improving short-term weight loss. For instance, in our preliminary work we demonstrated
that a weight loss workshop plus a short, daily ICT produced greater weight loss for individuals with higher-
than-average implicit preferences for high-sugar foods, compared to a robust attention control (i.e., the
workshop plus a sham training), and we found that adding gamification elements (e.g., story, music, levels) to
a rudimentary game produced additional 8-week weight loss for men (4.1% vs 2.5%). This project extends
previous work by evaluating the independent effects of gamification and ICT on long-term engagement and
outcomes. As such, 243 men with BMI = 25 will be recruited, with 15 participating in usability testing and 228
assigned to a 12-month mHealth weight loss program that prescribes digital self-monitoring and dietary and
physical activity targets. Utilizing an efficient 2 x 2 factorial design, participants will be randomized to receive
either a standard or fully-gamified program, comprised of a behavior change program featuring team-based
competition, and digital reinforcers for attainment of streaks and milestones, and also randomized to receive
either sham or active inhibitory control neurotraining. Aims include evaluating the efficacy of gamification and
ICTon weight loss, diet and physical activity at 12 months, as well as evaluating hypothesized mediators
(engagement and inhibitory control) and moderators (baseline frequency of video game play and implicit
preferences for ICT-targeted foods).