A Which? report testing ten private label and branded products found Tesco's Breaded Chicken Nuggets to be the worst, with just 50 per cent meat. A cocktail of fat, water, salt and oil make up the other half of the recipe.
As a result Tesco claims its nuggets recipe has changed, but failed to disclose to FoodandDrinkEurope.com - or the consumer watchdog - details of the new meat content.
Morrisons Crunchy Crumb Chicken Nuggets led on 68 per cent, with Asda, Sainsburys, Iceland, Bird's Eye and organic variety Georgia's Sake all faring moderately.
But none of the supermarket brands could match Burger King's Chicken Strips or McDonalds McNuggets, which contain 84 per cent and 76 per cent meat respectively.
Which? food and health researcher Julie Hunter said: "I think nobody really believes chicken nuggets are healthy, but some people might be surprised how little meat is actually in them, especially the supermarket varieties.
"As people become more aware it definitely does put pressure on manufacturers and retailers to meet consumer demands."
On announcement of the results last week, Which? contacted Tesco only to hear that the product has since been relaunched.
"We have been trying to push Tesco for the new meat content of its nuggets and so far they won't tell us," a source at Which? said.
"We have gone to Tesco to tell them about [the poor results] and they told us they've reformulated since the last test. But by how much?"
A Tesco spokesperson told FoodandDrinkEurope.com the relaunch had been planned for a while, as the company constantly updates and improves products. But the spokesperson could not confirm the meat content of the new chicken nugget recipe.
The fast food favourite first came under scrutiny two years ago, when Which? tested nuggets from restaurant chains and supermarkets, finding that takeaway products contained nearly 20 per cent more meat than those on shop shelves.
And although this time round all nuggets showed signs of improvement, Hunter said: "It's good news that nuggets are getting meatier but the quantity of meat in some is very disappointing.
"It's important that companies work harder to improve their nutritional value, particularly as nuggets are very popular with children."
In terms of market value, children's products contribute about €14-15bn to the overall €700bn food and drink market in Europe. But with a further 440,000 UK children predicted to become overweight or obese in the next two years and a quarter predicted to be obese by 2020, poor nutrition among children is clearly a critical issue needing urgent attention.
Food4Thought, a new British Heart Foundation campaign launched last month, uses billboards to attract the attention of 11 and 12 year olds with pictures of chicken nuggets and other foods covered by a 'censored' sticker.
The campaign is also targeting the government, food industry, local authorities, schools and parents in the hope that this will mount pressure on food retailers and manufacturers to revise recipes.