16/03/2016 10:29 AM AEDT | Updated 15/07/2016 12:51 PM AEST

Queensland Fast Food Outlets To Display Mandatory Kilojoule Information

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Close-up of a woman eating fries

It's getting harder to ignore the fact that the average fast food meal is 47 percent of an adult's daily energy needs, with another Australian state introducing mandatory kilojoule labelling.

Queensland is due to introduce legislation on Wednesday forcing fast food outlets and some cafe chains to display kJ counts for all menu items, following similar guidelines in NSW, the ACT and SA.

But does knowledge equal willpower when it comes to junk food?

A study of NSW's introduction of mandatory kJ labelling found that yes, labelling did change people's buying behavior.

The study, by the NSW Food Authority found that while customers didn't drastically improve their knowledge of energy intake and consumption, the simple act of displaying comparable kJ counts resulted in a 15 percent drop in kJ per purchase.

A Sydney University study found kJ information led to the reduction of roughly a small serve of hot chips or 960 kilojoules from the average daily energy intake.

Heart Foundation Queensland chief executive officer Stephen Vines said it was a simple way of comparing two products.

“If you know a deluxe hamburger with a large serve of fries is around 7000kJ or 80 percent of your daily food intake, you would think twice before ordering it, especially when you consider it would take three hours and 35 minutes of cycling to burn it off,” Vines said.

“The legislation is fantastic but we need to back it up with a community education campaign so that people understand how to measure their intake by kilojoules.”

The foundation's nutrition manager Deanne Wooden told HuffPost Australia there was a hope the mandatory displays would change the way fast food restaurants made their food.

"We want to measure the impact on what’s being offered in fast food outlets -- which hasn't been done before in Australia," Wooden said.

"We want to try and get a baseline of information around the kJ content of menu items now and then post implementation.

"While one purpose of mandatory labelling is to give consumers more information, the ultimate aim is to impact on reformulation and hopefully lead to fast food outlets offering meals with less kJs to consumers."

Victoria, WA, Tasmania and the NT are yet to introduce kJ labelling.

A study by Cancer Council Victoria and Heart Foundation Victoria this year compared current fast food labelling in Victoria to NSW's guidelines to show two out of nine fast food chains displayed best-practice nutrition information.

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