Project EAT (Eating Among Teens) is a public health study in the US of the eating patterns of almost 5000 teenagers. They were asked to complete a questionnaire about their lifestyle. The young people who reported eating a greater number of family meals per week reported significantly less substance use (cigarette smoking, alcohol and marijuana use) and significantly better academic success and better mental health than those eating fewer meals with the family. You may think these kids did better purely because they were the ones who got on better with their families, but the researchers took that into account – so it was something about the actual sit-down meals which made the difference. The study also found that teenagers who ate frequent family meals which had a structured, positive atmosphere, reported fewer unhealthy weight control behaviours than teenagers without such family meals.
Eisenberg, M.E. et al (2004). Correlations between family meals and psychosocial well-being among adolescents. Archives of Pediatrics and Adolescent Medicine, 158: 792-796.