Brain training on smartphones could help dieters to resist temptation, research suggests.

A study found using online games to boost willpower can help to cut 200 calories a day.

The “go/no-go” method involves schooling individuals to alter their responses to unhealthy foods.

Participants were asked to push a button when shown an image of healthy foods, such as broccoli - and to do nothing when junk foods, such as cheeseburgers and crisps, were on display.

Researchers said the short games can help to retrain impulses, making it easier to resist tempting treats.

Studies found that doing the online exercises for as little as 10 minutes a week for a month, was enough to boost weight loss efforts.

Scientists said the findings were “promising,” and said they were optimistic that wider use of the interventions could help Britain to combat it’s obesity epidemic.

Two in three adults in the UK are overweight or obese.

The research led by Cardiff University, published by Royal Society Open Science, reviewed a number of trials using such interventions.

In one of the studies overweight participants saw total daily calorie intake fall by 200. Another saw snacking on energy-dense foods fall by up to 20 per cent, in around four weeks, with weight loss of around one and half pounds, while weight of those in the control group rose.