Using two new common (Phaseolus) dry bean varieties developed for UK growing conditions, the BeanMeals project explored how to pursue 'fork to farm' systemic innovation in the food system to transform institutional catering and home-cooking towards healthier diets with lower environmental impact, while also enhancing local and national enterprise. Action research, underpinned by a new systems thinking framework, centred on six primary schools and ten households in Leicester and Leicestershire (UK), set against a review of city-, county- and national-level school food policies. Three demand scenarios were developed, based on increasing UK average daily consumption from 8.5 g to either 17, 34 or 50 g, together with three enterprise opportunities ('Community Enterprise', 'Artisanal Entrepreneurs' and 'Food Giants'), to satisfy these demands in different ways. The benefits and trade-offs of scaling UK beans were analysed, including assessments of overall benefits to health, benefits to the environment (which depend on the methods of land conversion and weed management used), and economic benefits (which depend on the scaling method employed).This article is part of the theme issue 'Transforming terrestrial food systems for human and planetary health'.