Health experts have sounded a warning over salt levels in popular kids food, with some fast food giants serving up single portions containing more than a day's recommended salt intake.

Key points: A new report analyses salt levels in kids meals at McDonald's, KFC, Subway and Hungry Jacks

A new report analyses salt levels in kids meals at McDonald's, KFC, Subway and Hungry Jacks Nuggets emerge as a key culprit in highly salted foods

Nuggets emerge as a key culprit in highly salted foods Health experts call for greater regulation of fast food in Australia

The fast food outlets were also found to use significantly more salt in some of their Australian meals than in the same food at their overseas stores, with experts saying a lack of regulation was to blame.

A new report by the George Institute for Global Health analysed the salt content in kids meals at KFC, McDonald's, Hungry Jack's and Subway.

It found a wide variation across the stores and among individual items, with nuggets and fries emerging as key culprits.

Top five highest salt levels in children's meals

Outlet Meal Portion size (g) Total salt (g) Hungry Jack's 6 nuggets kid's pack (including dipping sauce, small chips and water) 288 3.78 Hungry Jack's 3 nuggets kid's pack (including dipping sauce, small chips and water) 174 2.75 Hungry Jack's Cheeseburger kid's pack (including small chips and water) 210 2.75 McDonald's Happy Meal (cheeseburger, fries and water) 440 2.32 McDonald's Happy Meal (wholemeal snack wrap crispy, fries and water) 433 1.94

Source: The George Institute, March 2019

At 3.78g of total salt, Hungry Jack's six nuggets pack contained 108 per cent of a 4-8-year-old's recommended daily salt intake, the report found.

The average salt levels in the kids meals across the four outlets was 1.57g — 45 per cent of a child's recommended daily salt intake.

The report was prepared for VicHealth, which has seized on its findings to call for fast food outlets to scale back their salt use.

"An alarming 80 per cent of Aussie kids are eating too much salt with most of it coming from processed food and fast food takeaways," VicHealth dietician Sian Armstrong said.

"This research shows fast food doesn't have to be this salty.

"There is no reason why chicken nuggets at KFC and Hungry Jack's should be almost twice as salty as the chicken nuggets from McDonald's. The same goes for fries."

Among the key findings of the report was the significant difference in salt levels between the same item in Australia and the UK.

Salt levels in Australia vs UK

Outlet Meal Australian salt (g) UK salt (g) Hungry Jack's 6 nuggets kids pack 3.78 2.53 McDonald's 6 nuggets, small fries, water 1.59 0.95 KFC Popcorn chicken kids meal 1.58 1 Subway Ham mini sub kids pack 0.98 0.9

Source: The George Institute, March 2019

The George Institute's public health nutritionist Clare Farrand was the lead author of the report and said it was clear more regulation was needed in Australia.

"It is unacceptable that some children's meals in Australia are significantly saltier than similar meals purchased in the UK," Ms Farrand said.

"The fact that some companies produce the same foods with a lot less salt in the UK demonstrates that they can, and should for all countries.

"We know that some companies are doing better than others — all of the Subway kids' meals meet the UK targets (of less than 1.8g of salt per kids meal) — but clearly more needs to be done to reduce the salt content across the board."

The report makes a number of recommendations for both government and fast food outlets, including:

Establishing salt targets for children's meals.

Establishing salt targets for children's meals. Creating a regulatory monitoring scheme to assess industry compliance with established salt targets.

Creating a regulatory monitoring scheme to assess industry compliance with established salt targets. Increasing consumer awareness campaigns to inform about the health benefits of reducing salt intake specifically for children.

Increasing consumer awareness campaigns to inform about the health benefits of reducing salt intake specifically for children. Fast food outlets gradually reformulate high salt products to lowest levels of salt possible.

Fast food outlets gradually reformulate high salt products to lowest levels of salt possible. Making the healthier option the default option.

The fast food giants say they offer choice and low-salt options. ( ABC News )

Fast food outlets respond

McDonald's, Subway and Hungry Jack's responded to the report, each stating they offered parents and kids a selection of foods, including low-salt options.

"Subway will continue to provide guests with a range of menu choices and the option to have subs, salads and wraps prepared without additional salt or higher-salt ingredients such as sauce, pickles or olives," a spokesperson said.

"[Parents] can absolutely choose a Happy Meal with a cheeseburger and fries, or we have a wide range of other options, such as apple slices, grilled chicken, cherry tomatoes, water, and wholemeal snack wraps," a McDonald's spokesperson said.

And a spokesperson for Hungry Jack's said parents could request no added salt when ordering chips as part of its "have it your way" menu.

"Hungry Jack's has worked closely with suppliers of its fresh, quality ingredients to achieve reductions in saturated fats, sodium and sugar across its menu," the spokesperson said.

KFC did not respond to a request for comment before publication.