(P08-013-20) Effects of a Chrononutrition-Based Mobile App Intervention on Meal Timings and Weight Changes in Adults

Objectives: Evidence from nutrition studies that consider the circadian system (chrononutrition) has rapidly accumulated. The aim of this study is to evaluate the effects of a chrononutrition-based mobile application (app) on meal timings and weight changes in participants categorized as lean, normal weight, overweight, and obese.


Methods: A total of 3,816 adults aged 19-66 (mean age: 40.4±9.8 years, male: 72.1%) were recruited. The app, named “Reborn Magic,” enabled self-monitoring through the use of process motivators including gamification. The primary outcome was weight changes after a 4-week intervention. Other outcomes include waking time; timing of eating breakfast, lunch , and dinner; and bedtime on weekends and holidays. Physical condition score including feeling refreshed after waking up, concentration in the afternoon, and vitality after work were measured.

Results: Of the 3,816 adults enrolled in the Reborn Magic study, 1,835 completed the pre-post assessment (48.1% retention rate). Age was negatively correlated with waking time and dinner timing but had no correlation with the timing of breakfast, lunch, and going to bed. The rates of inappropriate meal time were 32.9%, 34.2%, and 61%, respectively. The time lag improved after the intervention (80.6±71.9→69.0±70.3,　83.8±59.9→72.7±62.0, 26.8±49.9→18.1±44.6, and 8.7±73.9→40.7±55.0 min, respectively), although they did not improved except bed time on weekends. Physical condition scores (out of 10) were significantly increased (6.6±2.3 to 8.2±2.0 points). Significant weight loss was observed in participants with overweight and obesity (-0.33±1.23 and -0.49±1.39 kg, respectively), while in participants in the lean category, significant weight gain was observed (+0.37±0.99 kg). However, there were no weight changes in participants with normal weight.

Conclusions: These results demonstrate the chrononutrition-based mobile app’s efficacy with regard to adjusting weight through the improvement of circadian rhythm. Further studies, including randomized controlled trials, are required to confirm these results.

Funding Sources: JSPS KAKENHI