Increased vegetable consumption in Japan using an incentivized health communication campaign with a quiz.

Dietary habits, particularly vegetable consumption, play a crucial role in preventing noncommunicable diseases. However, despite international guidelines advocating daily vegetable intake, adherence remains low across many populations. As a result, more focused efforts to boost vegetable consumption at the population level are essential. This study aimed to assess the impact of a health communication campaign (HCC) in City A, which combined information dissemination and incentives to promote vegetable consumption. In 2021, a new app-based vegetable quiz was introduced as part of the ongoing campaign, which had been implemented since 2017. Participants earned 10 points per correct quiz answer, which could be redeemed for product certificates, with a maximum of 30 points. To evaluate the effectiveness of the quiz, we analysed vegetable intake data from 786 quiz users. A multiple regression analysis was conducted to consider factors such as sex, age, body mass index, pre-campaign points, prior vegetable intake, and frequency of food recording during the campaign. We ensured robustness of the results by analysing data from 605 individuals whose vegetable intake had been tracked one year earlier, during a non-incentivized version of the campaign. The results demonstrated that participants who completed all three quizzes consumed 10.7% more vegetables than non-participants. Year-over-year comparisons further showed a significant increase in vegetable intake among frequent quiz participants compared to the previous year, highlighting the positive impact of gamified quizzes on vegetable consumption. These findings suggest that incentivized HCC, especially those incorporating gamification elements, can be highly effective in encouraging healthier eating habits.