Many children have such appalling knowledge of food sources they think pasta comes from animals, eggs come from cows and fish fingers are made of chicken, according to research.
More than a quarter of primary school children think cheese comes from plants while one in ten teenagers say fruit pastilles are healthy.
The findings have been revealed by the British Nutrition Foundation (BNF), which says teachers need more support to widen children’s knowledge of nutrition beyond what they glean off the internet.
The BNF surveyed 5 040 children aged five to 16 as part of its annual Healthy Eating Week. Among the most worrying findings, 13 percent of eight to 11-year-olds claimed pasta comes from animals.
A fifth of five to seven-year-olds believe fish fingers are made of chicken and 14 percent believe bacon is the produce of cows, sheep or chickens.
Nearly a third of primary school pupils claimed cheese came from plants, with 22 percent citing the same source for prawns. One in ten of 11 to 14-year-olds surveyed did not know that carrots and potatoes grow underground. Some cited vines or trees as possible sources.
A quarter of 14 to 16-year-olds think strawberry jam contributes to your "five-a-day", while 11 percent cited fruit pastels and eight percent, crisps.
Roy Ballam, of the BNF, said: "We can’t control what children access on the internet and elsewhere but we can ensure teachers are equipped with accurate information. However, research we conducted last year among primary school teachers showed that seven in ten had not undertaken any professional development in 'food' during the past two years.
"It has never been more important for schools and teachers to be armed with the correct information so that children and young adults are able to decipher between fact and fake news."