The group from the National Centre of Excellence in Functional Foods at the University of Wollongong made the discovery after investigating more than 500 dietary studies done in the past 25 years.

Associate Professor Peter Williams said there was a popular misconception that whole grains, pasta and other carbohydrate foods were too high in energy.

However, researchers found those who consumed cereals, pasta, bread, beans and nuts in a low-fat diet were more successful at losing weight and keeping it off than those on low-carbohydrate regimes.

"The evidence was clear that people who had more whole-grain cereal in their diet were less likely to be overweight, whereas low-carbohydrate diets were unsustainable over the long-term," Williams said.

Part of the secret of whole-grain foods was a low glycaemic index, meaning it filled people up quickly.

However,he warned the findings did not mean people could go "open slather on calorie consumption."

Whole grains are also believed to help ward off heart disease and diabetes.

Nutrition Australia WA chairwoman Dr Amanda Devine said the findings were good news for those who followed a healthy eating regime that included whole grains. "They are high in vitamin B, which helps you get energy out of other nutrients like proteins and carbohydrates," she said.

Australasian Society for the Study of Obesity figures show the overweight problem costs Australia up to A$1.5 billion a year.

From the May 9, 2007, Prepared Foods e-Flash