The 260 million publicly funded school meals served annually in Sweden generate 21.000 tons of food waste. At national level, school meals should meet the goal of food waste reduction, together with various other goals such as meeting nutritional requirements, being environmentally friendly and, most importantly, achieving high acceptance among schoolchildren. There is a preconception among kitchen staff that the most popular school meals drive food waste in Swedish school catering and that vegetarian dishes increase food waste, despite being less popular than meat options. By applying mixed methods, this study investigated possible goal conflicts between reduced food waste, high acceptance, and vegetarian options on the lunch menu. An overall aim was to gain knowledge on how lunch menus could be adapted for increased sustainability. Kitchen staff from 10 Swedish primary and secondary schools were interviewed to identify the most popular and unpopular meals, and food waste quantification data and lunch menus from 61 school canteens were analyzed. The results showed that, while the common perception of popular and vegetarian meals creating most waste was held by kitchen staff, it proved to be untrue. In fact, popular school meals and vegetarian options generated less waste than unpopular meals. A vegetarian paradox was detected in interviews, with vegetarian options considered unpopular but with several vegetarian options among the most popular dishes. Thus, school-catering units should stop serving unpopular meals and shift their focus to serving popular nutritious meals, including popular plant-based options, as part of efforts to make school meal schemes more sustainable. All rights reserved, Elsevier.