A survey undertaken by pasta sauce people Dolmio also found that clueless kids thought jam, milk, water and cereal counted as fruit and veg.
Researchers quizzed more than 500 families with kids aged eight to 15 about their eating habits, and although they concluded that overall, youngsters general knowledge of healthy eating is OK, there is still a lot of befuddlement as to what can be counted towards the five-a-day target.
Most kids (95 per cent) knew that it was important to chow down on five portions of fruit and veg a day, and most (96 per cent and 95 per cent) knew that apples and tomatoes could be counted, but a staggering 16 per cent also though jam could be part of the quota, while 15 per cent regarded a blueberry muffin as a fruit portion.
Milk and cereal were considered to be fruit and veg by 12 per cent of polled youngsters, whilst 6 per cent though water could be counted.
Nutritionist Juliette Kellow commented on the findings in The Independent, saying: "Parents have busy lives but something as simple as preparing healthy meals together or even growing tomatoes on the kitchen windowsill will make a huge difference to their children's understanding of the origins of natural foods."
More on Parentdish: How to sneak five a day into picky kids' food
Does this shock you? Do you sometimes wonder if kids are just trying to wind up researchers - and their parents?