Currently, social networks are part of the lives of adolescents, who make intensive use of them to relate to each other and to the world, making them a major factor in socialization. This has led to a great deal of scientific research on the influence of this means of communication in many areas of the life and development of adolescents, especially in the field of both physical and mental health. This paper reviews some relevant psychological phenomena associated with the use of social networks to understand their influence on adolescent behaviour; the main psychosocial risk factors for problematic internet use at this stage and their possible relationship with eating disorders based on recent research findings; as well as some proposals adopted within the European Union and in Spanish legislation for the control of harmful content on the Internet, especially those related to the advocacy of anorexia and bulimia, which until very recently escaped any possibility of control despite their importance for public health. Finally, we briefly discuss the potential of technology to implement these controls and present a research project for the detection and neutralization of apology of ED on Twitter, funded and implemented by the APE Foundation with the collaboration of the University of Zaragoza.