You don't know what your children need. They won't know either, if they're never allowed to live in such a way that they will learn to pay more attention to their bodies than to a book or a menu, calendar and clock.
You do know they need water, and some fruit and vegetables and protein and carbohydrates and enough oil (from nuts or meat or cheese or fish or something) to make their bodies function. If you make a variety of foods available, and if your children aren't shamed or ridiculed or controlled about what the can choose, they will deal with food in ways that most people don't believe could be possible.
People who have raised livestock or had pets who could go outside might have seen animals eat unusually sometimes. Maybe a dog or cat will seek out grass or something leafy. Sometimes a horse might forage differently than usual, or eat a little dirt. They know what they're doing.
When children have been able to choose, they can grow up knowing they need to not eat for a few meals, or they need just vegetables, or they need something salty. It does go against our cultural conditioning to think that people have instincts, but once someone has had a baby and smelled that infant's scalp and felt the reaction when the baby cries, it must be easier for them to consider that instincts are functional in people, it's just fairly taboo to discuss them.
So the purpose of eating can be medicinal. It can be for strength and health. It can be for stimulant purposes or for calming. It can be a social activity. It can be a nervous habit or a self comfort, so if you can maintain a situation in which your children are usually calm and comfortable, those last few will not be needed as much as they are with some people. Be a better friend and comfort to your children than food is. That is not accomplished by shame, control or rules.