A single Australian burger can contain more salt than an adult can safely eat in a day.
That's without chips, and even after four years of declining sodium in pizzas, burgers and takeaway chicken.
New research shows fast-food companies are using less salt in their products, but health experts say the reduction is not co-ordinated, and is also too little and too slow.
Too much salt is a killer, causing high blood pressure that leads to heart attacks and strokes. It has also been linked to bone damage and stomach cancer.
Research leader Dr Elizabeth Dunford, of The George Institute for Global Health and the University of Sydney, compared the salt content of more than 300 fast-food products over four years.
It will take government intervention to achieve significant sector-wide improvements, says Dr Dunford, whose study is published in the Medical Journal Of Australia.
The average Australian eats more than double the recommended four grams or single teaspoon of salt a day.
People can consume their entire daily quota in one burger, says Dr Dunford, who compared nutrition information on the Pizza Hut, Hungry Jacks, KFC, McDonald's, Subway and Domino's websites.
Overall salt content fell during the four years, but levels in side dishes rose.
Pizza Hut was the only brand to increase the amount of salt on its menu, mainly because of increased serving sizes and side dishes such as chicken bites.
"Salt levels in Australian fast food remain high. These small reductions in salt levels could be easily undone by the trend towards larger portion sizes,'' Dr Dunford says.
She urges Australia to adopt a strategy similar to the UK's government-led salt-reduction program, which has achieved lower salt levels than other countries.
"Salt reduction is one of the most cost-effective options for improving public health,'' Dr Dunford says.
Asked for comment, Professor Garry Jennings of the Baker IDI Heart and Diabetes Institute called for more action.
"The inconvenient truth is that there's too much salt in many commercial foods and being blind to it can cause significant damage,'' he says.
"Better labelling and a stronger commitment from processed food companies would go a long way to tackling Australia's burden of cardiovascular disease.''
The Heart Foundation's Dr Robert Grenfell described the findings as a step in the right direction.
"But we're mindful that what's in the actual product can, in some instances, vary from what's stated on the company's nutritional panels."
"Research suggests that if we cut the nation's salt intake by an average of three grams a day, we could prevent 6000 deaths every year.''