TEENAGERS bombarded by junk food adverts are much more likely to be obese according to the largest survey of its kind to link marketing and weight.

Adolescents who could remember seeing a junk food advert every day were twice as likely to be obese than their peers who could not recall any over a month.

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Social media advertisements were more likely to stick in the memory obese teens than marketing carried on other platforms, such as billboards and television, and adolescents from deprived communities were 40 per cent more likely than those from wealthier families to recall seeing junk food adverts every day.

The findings were based on a survey of 3,348 UK adolescents, aged 11 to 19, carried out by YouGov and commissioned by Cancer Research UK. Data was collected on their television viewing habits, diet and their body mass index.

Dr Jyotsna Vohra, a lead author on the study, said: “It’s particularly worrying that the poorest teens had the best recall of junk food ads.

"We can’t allow the industry free rein to target young people, especially as we know that eating habits adopted in childhood are more likely to remain into adulthood.”

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Since 2017, adverts for foods high in fat, sugar and salt have been banned on media - including television and online sites - aimed at children under 16, or where children under 16 make up at least a quarter of the audience.

Linda Bauld, professor of health policy at Stirling University and Cancer Research UK’s prevention expert, said more needed to be done.

She said: “This study found a strong link between exposure to junk food ads and an increase in teens’ risk of being obese, and suggests that the poorest are hit hardest

“Young people from more deprived backgrounds have the most to gain from a 9pm ban on unhealthy TV adverts.

"Urgent action is needed from Ofcom to support efforts to reduce the health inequalities between the poorest and richest in our society.”

The Scottish Government wants Westminster to ban broadcast advertising of all junk food before the 9pm watershed and has said it will seek to have those powers devolved unless the UK Government does so.

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The findings come as obesity and alcohol campaigners in Scotland called for more action to protect children from marketing.

Speaking at the Leave our kids alone! event in Edinburgh, Alison Douglas, chief executive of Alcohol Focus Scotland, said: “Exposure to alcohol marketing reduces the age at which young people start to drink, increases the likelihood that they will drink and increases the amount of alcohol they will consume one they have started to drink.

“AFS believes every child in Scotland should have the right to an alcohol-free childhood and more than 30 organisations, as well as the majority of MSPs, have pledged their support to end alcohol marketing in childhood.”

Lorraine Tulloch, of Obesity Action Scotland, who co-hosted the event with AFS, said: “Junk food marketing is big business in the UK with over £143 million spent on advertising crisps, confectionery and sugary drinks alone.

"Children are particularly vulnerable to these adverts and have reported wanting to lick the screen or pestering their parents until they get a certain product.”