We’re in an obesity epidemic and most people don’t know how to cook even very basic meals.
Make space for it, squish other classes if you need. Make it mandatory, everyone has to take it. Maybe even ongoing through multiple grades.
Edit: Rice, beans, and even basic meats are cheap. To eat healthy you don’t need your meal to be 100% Bell peppers and tomatoes.
500 grams of broccoli doesn’t fill you as much as 500 grams of minced meat. Fruits and veg are mostly water. You need some creativity and a lot of supporting carbs and fat to make a vegetable centered dish as filling as a simple meat based dish. I can eat an entire broccoli and be hungry five minutes later, but after half a kilogram of meat I could be satiated for the rest of the day.
Milk wouldn’t work for a lot of people because of lactose intolerance and the price of alternatives like almond juice can vary widely from town to town. That said, dairy and dairy alternatives are a great way to make a vegetable based dish more nutritious and filling.