There are an abundance of studies showing the link between office productivity, or even simple human happiness, with the consumption of fruit (and vegetables). Here’s a simple reference guide…
“Let Them Eat Fruit! The effect of fruit and vegetable consumption on psychological well-being in young adults: A randomized controlled trial.” Connor, Brookie, Carr, Mainvil, Vissers. PLoS One, February 2017.
“On Carrots and Curiosity: eating fruits and vegetables is associated with greater flourishing in daily life.” Connor, Brookie, Richardson, Polak. British Journal of Health Psychology, May 2015.
“Many apples a day keep the blues away: daily experiences of positive and negative affect and food consumption in young adults.” White, Horwath, Connor. British Journal of Health Psychology, November 2013.
“The Physiology of Willpower: Linking Blood Glucose to Self-Control.” Gailliot, Baumeister. Personality and Social Psychology Review, November 2007.