What minimum fraction of the RDA for key nutrients children 10-12 years age should be provided by public school lunches?

There's no single, universally mandated minimum fraction of the Recommended Dietary Allowance (RDA) for key nutrients that public school lunches must provide for children aged 10-12. The requirements are complex and vary.

Instead of a percentage of the RDA, school lunches are evaluated based on the Dietary Guidelines for Americans and standards set by the U.S. Department of Agriculture (USDA)'s National School Lunch Program (NSLP). These standards specify nutrient minimums and maximums for things like calories, fat, sodium, and specific vitamins and minerals within the context of a complete daily diet. They don't aim for a certain fraction of the RDA within the lunch itself.

The NSLP aims to contribute significantly to a child's overall daily nutrient intake, but it's understood that school lunch is only one component of a child's total diet. Parents are responsible for the rest of their children's nutritional needs. The program's guidelines are designed to ensure lunches are healthy and provide a good foundation, not necessarily to completely fulfill the RDA within a single meal.