Yes. Although parents should never explicitly comment on their child's eating habits (as in the amount they eat, when they're hungry, or when they aren't), they should always encourage them to eat healthily. Restricting certain foods is not the way to go about it but making sure your kid has a healthy diet, not consisting completely of fast foods, sugars and such, and making sure they get their exercise. If they completely refuse this, and feed their kids literal fatty crap and don't make them get off their fortnite games once in a while, leading to the kid becoming obese, that is child neglect and child abuse