I often hear this from parents who have teenagers with eating disorders: they try their best to say the right things when it comes to food, but their teen reacts with an angry outburst or won’t talk to them at all. Eating disorders affect almost every aspect of a person, and their families – and communication is definitely an area that can be deeply affected.

First, know that conversations will not go perfectly, no matter what you say. They may not even go smoothly most of the time. Being able to...