Childhood and adolescence is a period of rapid development, and both are critically important to developing a foundation for good physical and mental health in adulthood. Unfortunately, studies have shown that young people are not meeting many health-promoting recommendations, particularly when it comes to eating a healthy diet. In Australia, fewer than 5% of adolescents eat the recommended amount of fruits and vegetables and they are much more likely to be regularly eating nutrient poor, high sugar foods such as lollies, snacks and baked goods. These dietary patterns are understood to have negative consequences for future physical health, but the scientific research also shows that what children and adolescents are eating is critically important to their brains and mental health as well. What do we know? Researchers around the world have investigated the relationship between what children and adolescents are eating and emotional and behavioural problems. Many studies from a multitude of countries now show that a dietary pattern higher in added sugar and fats, processed and junk foods is linked to more emotional and behavioural problems in children and adolescents. We have also shown that unhealthy diets are related to smaller parts of the brain that are critical to learning and memory, as well as mental health. The good news, however, is that these studies suggest that a good quality, healthy diet – high in fruits and vegetables – can be protective of mental health, reducing the likelihood for such problems in this population. What do we need to do now? Childhood and adolescence are critical windows of development; during this time, many psychiatric conditions emerge for the first time. Many common mental disorders, such as depression and anxiety, often arise in our early years and can be long lasting. Happily, there is good evidence to suggest that eating a healthy, good quality diet can be protective, and can reduce the chances of developing a mental disorder. Early life, adolescence in particular, is a time of transition to adulthood where many lifelong habits are being established. This time is highly important to establishing healthy habits, and educating young people on nutrition, food and cooking. What are we doing? We are running many studies investigating the role that diet plays in adolescents’ mental health, as well as the pathways by which this relationship might work. This research program aims to identify key targets for intervening to improve adolescents’ diets and – thus – their mental health. You can read about some of these studies here, here and here.