Almost two-thirds (65.4 per cent) of the calories eaten by children in Britain come from “ultra-processed foods”, a study has found. 

Examples of ultra-processed foods include chocolates, ice cream, biscuits, packaged bread, breakfast cereals and jars of pasta sauce.

Researchers from Imperial College London studied data from more than 9,000 children who grew up near Bristol and were followed from the age of seven to their mid-20s. 

Those who ate the most ultra-processed foods throughout childhood and adolescence were found to have a BMI 1.18 points higher than those who ate the least by the age of 24. 

They also had 1.53 per cent more body fat and, on average, weighed over eight pounds more. 

Childhood eating habits extend into later years

Ultra-processed foods are defined by the researchers as “food and drink formulations of multiple substances, mostly of exclusive industrial use (e.g. high-fructose corn syrup), are manufactured through a series of complex industrial processes (e.g. hydrogenation) and often contain cosmetic food additives (e.g. colours, flavours and emulsifiers) that disguise any undesirable sensorial properties of the final product”.

Writing in the journal JAMA Paediatrics, the study’s authors suggested that eating patterns established in childhood extended into adulthood, potentially setting children on a lifelong trajectory for obesity and a range of negative physical and mental health outcomes.

Prof Christopher Millett, professor of public health at Imperial College London, said: “Our findings show that an exceptionally high proportion of their diet is made up of ultra-processed foods, with one in five children consuming 78 per cent of their calories from ultra-processed foods.

Dr Eszter Vamos, senior clinical lecturer in public health medicine at Imperial College London, said: “Childhood is a critical time when food preferences and eating habits are formed with long-lasting effects on health.”

Industrial food processing sees food modified to change its consistency, taste, colour, shelf life or other attributes through mechanical or chemical alteration. This is also typically lacking in traditional, home-made meals.

The work is the first to look at the link between the consumption of ultra-processed foods and obesity in children over a long period of time, with findings broadly applicable to children across the UK.

The researchers highlight that a limitation of the study is its observational nature, and that they are unable to definitively show direct causation between consumption of ultra-processed foods and increases in BMI, body fat and weight.

Socio-economic factors at play

Prof Gunter Kuhnle, professor of nutrition and food science at the University of Reading – and who was not involved with the study – said: “The results of this study are not surprising: children who consume a lot of ‘ultra-processed’ foods are most likely to be less healthy and more obese than their peers with lower intake. 

“The interpretation of these results are, however, much more difficult. Apart from the limitations of the definition of ‘ultra-processed foods’, the outcome of the study is heavily confounded by socio-economic factors: children living in more deprived areas and from families with lower educational attainment and lower socio-economic status had the highest intake of ultra-processed foods. 

“Unfortunately, these children are also at highest risk of obesity and poor health, as there are still considerable health inequalities in the UK and socio-economic status is an important determinant of health.”

However, Dr Duane Mellor, a registered dietitian at Aston University, criticised the methodology of the study and the broad definition of what constitutes ultra-processed food.

“Overall, this study risks suggesting that all foods which are processed are bad, whereas this is probably only really the case when they are higher in fat, salt and sugar and lower in fibre,” he said.