Levying taxes on unhealthy food items could help encourage people to eat fruits and vegetables and whole grains, scientists have observed .

Psychological scientist Leonard Epstein at University of Buffalo sought to determine the persuasiveness of sin taxes and subsides in the laboratory.

Epstein and team recorded the shopping habits of mother-volunteers who were given laboratory "money" to shop for a week's groceries for the family.

Experts found that raising the prices of unhealthy foods or discounting the price of healthy foods proved as effective measures in reducing calories purchased over subsides.

Boffins found that taxing unhealthy foods reduced overall calories purchased while subsidizing the prices of healthy food increased overall calories purchased without any change in the nutritional value.

The findings have been published in Psychological Science, a journal of the Association for Psychological Science .