Cultivate correct ideas
Conceptually, let children know that food is hard to come by, and let children know how to cherish food. Over time, children can remember the correct concepts.
Establish principles
When children are young, parents can make principles for their children, such as how much to eat, not throwing leftovers, eating leftovers by themselves and so on. Parents should not waste food, let alone help their children eat leftovers. Parents can urge children to eat as much as possible according to the situation.
Set a good example
Whether eating out or at home, parents should set a good example for their children. Usually the family goes out to eat, orders less, and packs leftovers. When eating buffet, teach children to eat as much as they want, and don't waste food if they don't eat enough.