Financial incentives aimed at encouraging healthier food choices are catching on all over the world, says a report.

Workplaces in the United States are offering incentives for weight loss, while in a London-based study, dieters got paid when they dropped pounds, said the NPR report.

Researchers are studying how food price manipulations may influence what people buy. To create successful incentives, a policy needs to specifically target the people whose behaviour it's trying to change, the report quoted Yale behavioral economist Dean Karlan as saying.

"So in the case of broccoli you'd want to find out who's not eating broccoli and then pay them to eat it," he says. "You don't want to necessarily make broccoli cheaper for those who are already buying plenty of it, you want to target those who don't buy enough fruits or vegetables. It could be very tricky to structure such an incentive."

To find out how prices influence choices, researchers at the University of Buffalo set up an experiment where they could control food prices and see how shoppers responded. When the costs went down, people bought more of the healthy foods, said the researchers.

The researchers found that when a hefty tax on high-calorie, low-nutrient foods were placed, people stopped buying so much junk food.

The researchers say their findings suggest that the taxes were more effective than subsidies.