The amount of salt on the menus of the six biggest fast food companies varies greatly from nation to nation, according to a study that calls for regulations to curb sodium intake.
And despite Australian fast food on average sitting in the middle of pack, one burger set the record for breaking the upper daily limit.
Researchers in Australia, Britain, Canada, France, New Zealand and the United States looked at the salt content of 2124 food items sold by six fast food chains in April 2010.
The study, which appears in the Canadian Medical Association Journal, included popular items such burgers, chicken nuggets, pizza, salad, sandwiches and fries.
Lead author Elizabeth Dunford, a PhD student at the George Institute in Sydney, says the level of salt in Australian fast food is better than Canada and the United States, but worse than the United Kingdom and France.
She says burgers rated the worst when it came to salt content per serve, with the Hungry Jack's Ultimate Double Whopper containing 6.3 grams of salt. The next worst offender was the Burger King Angus bacon and cheese burger from the United States with 5.2 grams.
Exceeding recommended intake
According to the Nutrient Reference Values for Australia and New Zealand, the adequate intake level for salt is 4 grams per day, with an upper limit of no more than 6 grams.
Dunford says previous research shows Australians are on average consuming 8 to 12 grams of salt a day, with 75 per cent coming from processed foods.
Too much dietary salt has been linked to higher blood pressure and other adverse health effects.
Previous studies have shown cuts in salt intake can result in a significant reduction in deaths.
"The main outcome of high salt is high blood pressure levels and that is the leading risk factor for cardio vascular disease and stroke, which is the number one cause of death in Australia," says Dunford.
Several countries have started to curb salt intake, with the latest successes coming from voluntary salt reduction targets and labelling of foods.
"We think the reason for [the low salt levels in the UK] is that they have a national salt reduction campaign," says Dunford.
"In Australia we started that process with some processed foods, but we're a little behind in other foods. We're heading in the right direction."