One way to help prevent an eating disorder would be to do some research on how eating disorders are caused. Educated yourself on anorexia nervosa, bulimia nervosa, binge eating disorder and OSFED. Awareness of these disorders will help you avoid judgmental or mistaken opinions about food, weight, body shape and eating disorders.
Make sure to keep a well balanced diet, and do some research about what a well balanced diet includes.
I hope this helps you!