Increasing fruit and vegetable consumption in a shift towards more plant-based foods is considered a key component of a healthy and sustainable diet. Recent experimental work suggests that behavioural insights-based interventions in the immediate choice context may create opportunities for sustainable food-behaviour change. Among the many actors and elements of a complex food system, supermarkets are in a unique position as main gatekeepers to curate the interface between supply and demand and steer both in more sustainable directions. Sustainability-oriented retailers can use innovative behavioural tools to promote healthier and climate-friendlier foods (such as vegetables) while meeting the “triple bottom line”. A real-life supermarket trial in Denmark tested if multi-layered nudges can increase the purchase of fruit and vegetables. The intervention led to small increases in sales. These findings showcase the possibility that supermarkets, in principle, have agency and ability to nudge consumers towards more sustainable diets. To meaningfully shift consumers’ consumption patterns, supermarkets need an open sharing of best practices and the use of a sound methodology to better understand and effectively change consumer behaviour. In partnership with stakeholders, supermarkets could play a more active role in fostering a sustainable food transition by employing “nudges for good”.