A good way to make your son/daughter accept healthy food is to relay the benefits of healthy food and the disadvantages of unhealthy food and show what will happen to them if they continue eating it. Try to indirectly shame them by saying if they stay like this, they will become fat and less attractive. For example, this will make the child rethink their choices and try to become the best version of themselves.

Young people are really hard to get out of something, especially when they are addicted to it. That's why it's a big problem to let kids eat as much fatty food as they like because this will make them extremely unhealthy and will affect their future lives.