"No dessert for you!", "Do you want me to give you fish for dinner?", "If you keep this up there'll be no biscuits for you", "If you're not careful there'll be no dinner!". Depriving children of food, restricting certain foods or forcing them to others is not a valid strategy to correct behaviour. Let's explain why.
There is a basic rule when educating children: food cannot be used as punishment or as reward. Eating habits should be a sacred part of a child's routine and beyond any negotiation, assessment or consequence of other actions.
Punishing or rewarding with food can leave the child making negative associations with food.
The relationship between food and our emotions starts from early childhood. Food strengthens and nourishes and if we load it up with negative emotions it loses its main role, ceases to be something natural and can even distress the child. So, before using food as a weapon, try these tips:
Regularly talk to your child about the benefits of eating well (to grow big and strong, to avoid getting sick, etc.). Children need to grow up thinking that their bodies are so important that they need to be cared for with a healthy diet. This stops them from seeing healthy eating as a duty and helps them see it as part of the normal routine.
In summary, the shortest, most effective way is to encourage and reinforce the behaviour you want them to repeat, praising good behaviour instead of punishing the bad, and leaving food out of any punishment.