The Parker twins ate different diets
An experiment involving identical twin brothers has provided dramatic evidence of the impact that food addictives can have on a child's behaviour.
Christopher and Michael Parker, aged five, were put on separate diets for a fortnight.
But only Michael's diet was completely free of food additives.
After just two weeks Michael had become more assertive and calmer than his brother.
I can't believe the changes that Michael has shown in his
He also outperformed him on IQ tests.
Their mother Lynn Parker, from Crewe, Cheshire, told the programme: "The twin that came off the additives has been conforming a lot and has developed a sense of humour and is a lot more talkative.
"I can't believe the changes that Michael has shown in his
behaviour and as a result the knock-on effect that it's had with the rest of us as well."
During the experiment Michael was banned from eating chocolate and sweets, fizzy drinks, flavoured crisps and caffeine.
He was allowed additive-free goods such as ready salted crisps, fruit, banana chips and some yoghurts.
In IQ tests before the experiment the twins each made the same mistakes and completed them in exactly the same time.
Two weeks later, they conducted the same tests and Christopher had improved 10% but Michael had improved by 25%.
Professor Kevin Morgan, of Cardiff University, said school meals were a key area for improving children's health and behavioural development.
"Our research suggests that between 32p to 40p per primary school meal is what is allocated to the food ingredients and that is just simply not enough to
provide a good nutritious meal for a young primary school child."
Maurice Hansen, author of E for Additives, said: "Children who eat a lot of undesirable additives throughout their life and the bad food that goes with undesirable additives are going to finish up with a declining educational standard with a declining behavioural standard."
He said if undesirable additives were removed from a child's diet he would expect that child to show better concentration, increased IQ and be better behaved.
Ian Tokelove, of the Food Commission, called on the government to investigate the use of additives in children's food.
The experiment was featured on the ITV1 programme Tonight With Trevor McDonald.