Status of online diet management program users in Japan during the 2020 Coronavirus disease 2019 pandemic.

The spread of coronavirus disease 2019 (COVID-19) has led to drastic changes in people's lifestyles, including teleworking and restrictions on socializing. In the context of observing social distancing for preventing infection, the need to maintain fitness and health has attracted particular attention. We aimed to determine the relationship between the increase in the number of active users of online diet management applications and COVID-19 infection rates in Japan. A total of 1.5 million rows of log data was analyzed. The active number of users of online diet management applications increased with increase in the number of COVID-19 infections. The active user number in Kanagawa Prefecture, where the first cases of COVID-19 were reported in Japan, was particularly high. Moreover, there was a significant increase in the user number in prefectures under a state of emergency when compared to that in prefectures not under a state of emergency. The social anxiety caused by COVID-19 is expected to increase the demand for online health management applications further. The use of such programs can aid in achieving social distancing while enabling users to maintain healthy lifestyles.