Gustaaf Haan studied Logic and Philosophy in Amsterdam. He works at Questionmark, a think tank dedicated to a healthy and sustainable food system. Questionmark gives unsolicited advice to power holders in the food system and inspires them to take ever bigger steps forward. One of Questionmark's most impactful projects is Superlist, a comparative assessment of supermarkets and their contribution to sustainable food. A major indicator in this assessment is the extent to which supermarkets reduce the sales of meat.