This study investigated if a Mediterranean-style diet supplemented with fish oil can improve mental health in people suffering depression. Participants were randomly assigned to receive the intervention involving fortnightly food hampers and cooking workshops for three months and fish oil supplements for six months or instead to attend fortnightly social groups. After three months, participants in the intervention consumed more vegetables, nuts, legumes and wholegrains and included greater vegetable diversity. They also had fewer unhealthy snacks and less red meat or chicken. This group also had a greater reduction in depression and improved mental health. Both the improved diet and mental health were maintained at six months. There was also a benefit from the fish oil supplements.