This report sets out how school meals can help build a food system fit for the 21st century. New modeling work presented in this report shows that cultivating healthy and sustainable dietary habits is one of the best investments we can make for tomorrow. Rethinking food systems, from production to consumption, has never been more urgent. The world is facing a global nutrition crisis, with malnutrition affecting most of the population, either as hunger, food insecurity, obesity, or diet-related diseases. Many countries experience multiple malnutrition burdens at the same time and very few are on course to meet nutrition related Sustainable Development Goals (SDGs). At the same time, the need to feed an increasing population, coupled with prevailing agricultural practices and unsustainable food production and consumption trends, has altered the equilibrium of our planet, causing depletion and pollution of natural resources, habitat and biodiversity loss, deforestation, ocean acidification, and climate change. Food systems contribute to a third of all human-induced greenhouse gas (GHG) emissions. A third of all food is wasted along the value chain, accounting for 8%-10% of GHG emissions through its production. Food production accounts for 70% of freshwater use, and is the principal driver of biodiversity loss, mainly due to the conversion of natural ecosystems for crop production or pasture. These environmental changes affect our ability to produce high quality foods, further compromising food security and nutrition. These changes are especially damaging for countries in the Global South that will bear the brunt of the climate crisis sooner and more intensely than many other parts of the world.