Purpose_The goal of this paper is to explore the possible synergetic effects between lean philosophy and green endeavors in improving resource efficiency in the food sector. To that end, it is investigated how a proper and tailor-made adaptation of the lean six sigma root cause analysis method could help in overcoming the complexities of increased resource efficiency in food production. Design/methodology/approach_The case study concerned reduction of waste at an industrial production line of a dough-based product, through the implementation of the lean six sigma tool. Findings_An achievement of a 50% reduction of waste on the studied process line was reached, thus exceeding the initial improvement goal. Research limitations/implications (if applicable)_While the explicit findings on the specific root causes of waste on this actual production line are not immediately transferrable to other cases, they show that applying this method to identifying and eliminating root causes of waste for other products and processes in the food sector could not only reduce costs but also contribute to more resource-efficient and sustainable industrial food production. Practical implications (if applicable)_ Political and public high interest in environmental and social sustainability associated with food waste render this an important development. Originality/value_ While the potential of linking green and lean efforts has been acknowledged, the application of the lean six sigma methodology for more sustainable food production has not yet been explored. This paper contributes to this research.