The common perception that fresh fruits and vegetables are more expensive than packaged snack foods may not be correct after all, a new study finds.

A number of studies have suggested that chips, cookies and other high-calorie snack foods are generally cheaper than fresh produce, and the alleged price gap has taken some blame for Americans’ less-than-ideal diets and bulging waistlines.

But the new study, reported in the American Journal of Clinical Nutrition, suggests that the inverse relationship researchers have found between calories and price - higher-calorie foods being cheaper - is mainly a matter of algebra.

“When you consider the prices that people actually see at the store - total price and unit price - fruits and vegetables are actually cheaper,” said researcher Leah M. Lipsky, a Ph.D. candidate in nutritional sciences at Cornell University in Ithaca, New York.

The problem, she explained in an interview, is a matter of math.

Researchers have looked at the question by comparing the number of calories per gram in a given food with its price per calorie. This creates a comparison where the two variables share a common component - calories, in this case. And the simple properties of math mean that high-calorie foods will appear cheaper.

“Algebra has been creating the inverse association between (calorie) density and price,” Lipsky said.

For the study, Lipsky collected price information on various snack items and fresh produce from one U.S. supermarket chain. When she looked at the question in terms of calories per gram and price per calorie, fruits and vegetables did appear to be more expensive.

However, when it came to the prices that consumers see - the actual price and the unit price, which gives the product’s cost per gram of food - fresh produce was generally cheaper than snack food.

Lipsky pointed out that people probably take many things into consideration when choosing whether to buy fresh produce - the time it takes to prepare, whether they have the storage for it and whether it might go bad before they eat it, for instance.

But the current findings, she said, suggest that consumers should not be deterred by the popular notion that fruits and vegetables are too expensive.

SOURCE: American Journal of Clinical Nutrition, November 2009.