The same children's meals at popular fast food chains have been found to contain hugely varying levels of salt in different countries, which campaigners say shows that the companies could reduce levels if they wanted to.
Research by World Action on Salt and Health (Wash) found that a KFC kids meal in Costa Rica contains 18 teaspoons more salt than the same meal in the UK.
Its analysis of children's meals sold in fast food restaurants in 37 different countries also revealed that eight out of 10 meals contain more than 1g salt per serving.
The maximum recommended salt intake for children aged four to six is 3g a day, while it is 5g for seven to 10-year-olds. Anyone older should eat no more than 6g of salt a day.
The UK performed better than most countries, with its Burger King kids meal burger and fries containing 1.06g of salt and its Subway Kids Pak turkey sub containing 1g, compared to Finland (2.54g) and Germany (1.5g) respectively.
It was also rated lowest of all for its KFC popcorn nuggets and fries meal, which measured at 0.9g of salt per serving, while the McDonald's Chicken McNuggets Happy Meal also had the lowest at 0.78g.
The highest sale levels in these restaurants was found in Costa Rica's KFC at 5.34g and McDonald's in Turkey at 2.4g.
Wash said that too much salt in childhood habituates youngsters to the taste of salt, and puts up blood pressure, which leads to strokes and heart failure.
The group is calling for all food manufacturers to universally reduce the salt content of their products, to help achieve the target of 5g salt a day.
Nutritionist and international programme lead at Wash, Clare Farrand, said: "The fact that these fast food chains are able to produce less salty children's meals in some countries means they can do the same in all countries, and should immediately.
"All children, regardless of where they are from, should be able to enjoy the occasional meal out, as a treat, without putting their health at risk."