If food loss and waste (FLW) were a country, it would be the third leading cause of greenhouse gas emissions. FLW also burdens waste management systems and exacerbates food insecurity, , contributing significantly to the three global crises of climate change, nature and biodiversity loss, and pollution and waste. PRECIOUS, an transdisciplinary alliance of 20 entities from 11 EU countries, believes that reliable data on the environmental impacts of FLW is crucial for accelerating EU progress towards climate targets and reducing environmental impacts (including biodiversity) across the food supply chain. The project´s collective understanding is that the challenge goes beyond measuring the amount of food saved or CO2 emissions. When food is wasted, valuable and limited resources such as water, land use, and energy are lost, while 8.9% of the worldwide population is suffering from hunger accordingto FAO, therefore, depleting the planet's natural resources. It is critical to broaden our understanding of the issue to transform the food system and raise public awareness that motivate change. PRECIOUS aims to contribute to the transformation of food systems by addressing existing data gaps and developing a unified and openly accessible evaluation framework to quantify the economic, environmental, and social impacts of strategies to reduce FLW, taking into account potential rebound effects. The project will engage stakeholders from 2 Use Cases (Spain and Greece) and 3 Co-creation and Replication Nodes (Poland, Lithuania, Hungary) to address systemic causes across geographical boundaries. The project aims to induce a fundamental change in attitudes and behaviours towards food consumption and disposal through collaborative efforts and innovative methods, fostering a more just and sustainable EU food system.