The study featured 405 participants, all university students, who kept a daily diary for 13 consecutive days. Each day, they recorded the number of servings they had of fruits, vegetable, desserts and various fried-potato dishes.
They also filled out a daily questionnaire intended to measure creativity, curiosity, and psychological flourishing. Specifically, they responded to statements such as “Today, I was engaged and interested in my daily activities” on a one-to-seven scale (“strongly disagree” to “strongly agree”). They also responded to additional items designed to measure their general emotional state that day.
The results: People who ate more fruits and vegetables over the 13-day period reported higher average levels of curiosity, creativity, and positive emotions, as well as engagement, meaning and purpose.