A brain-training game could help children choose a healthy snack instead of chocolate and other high-sugar foods.
The seven-minute computer game, developed by the University of Exeter, resulted in children making healthier choices when given a choice of food afterwards.
Children played the game by viewing images of healthy food and pressing a button but doing nothing if unhealthy foods were shown.
"The sight of foods like chocolate can activate reward centres in the brain at the same time as reducing activity in self-control areas," said Lucy Porter, the lead researcher on the project.
"Our training encourages people to make a new association - when they see unhealthy food, they stop."
Researchers had more than 200 schoolchildren ages four to 11 play the game. Along each image of food, there was a cartoon face - happy for healthy food, and a sad face for unhealthy food.
"We didn't see a total turnaround in favour of choosing healthy options, but these increased from about 30 per cent of foods chosen to over 50 per cent in children who did the brain training," said Porter.
Children were asked to hit the spacebar when they saw a happy face, and do nothing if they saw a sad face. Afterwards, they played a shopping game where they had to choose a limited number of food items in one minute.
Meanwhile children in control groups - who were shown happy and sad faces mixed evenly between healthy and unhealthy foods, or images which were not food-related at all - showed no change in food choices.
"Many health promotion schemes rely on education and willpower and require a lot of time, staff and money, but our game potentially sidesteps these issues by creating a free, easy tool for families to use at home," Porter said.
"The research is at an early stage and we need to investigate whether our game can shift dietary habits in the long term, but we think it could make a useful contribution."