Children of mothers who eat junk food more likely to be overweight – study

Children of mothers who consume ultra-processed foods such as ready meals, sugary cereals and biscuits are more likely to grow up overweight or obese, a study suggests.

The link between a mother’s diet and her child’s obesity risk is independent of other lifestyle risk factors, including the child’s own consumption of ultra-processed food, according to the research. The findings are published in the BMJ.

Researchers at Massachusetts general hospital and Harvard medical school cautioned that further work is needed to confirm these findings – and to understand the factors that may be responsible.

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But they say mothers may benefit from limiting their intake of ultra-processed foods, that dietary guidelines should be refined, and financial and social barriers removed to improve nutrition for women of child-bearing age and reduce child obesity.

“Maternal consumption of ultra-processed food during the child rearing period was associated with an increased risk of overweight or obesity in offspring, independent of maternal and offspring lifestyle risk factors,” the researchers wrote.

“Further study is needed to confirm these findings and to understand the underlying biological mechanisms and environmental determinants.

“These data support the importance of refining dietary recommendations and the development of programs to improve nutrition for women of reproductive age to promote offspring health.”

According to the World Health Organization, 39 million children were overweight or obese in 2020, raising the risk of heart disease, diabetes, cancers and early death.

Ultra-processed foods, such as packaged baked goods and snacks, fizzy drinks and sugary cereals, are commonly found in modern western-style diets and are associated with weight gain in adults. But until now it has been unclear if there is a link between a mother’s consumption of ultra-processed foods and her offspring’s body weight.

The researchers drew on data for 19,958 children born to 14,553 mothers in the US.

A range of other potentially influential factors, known to be strongly correlated with child obesity, were also taken into account. These included the mother’s weight (BMI), physical activity, smoking, living status (with partner or not) and partner’s education, as well as the child’s ultra-processed food consumption, physical activity, and sedentary time.

The results showed that a mother’s ultra-processed food consumption was associated with an increased risk of her offspring being overweight or obese. For example, a 26% higher risk was seen in the group with the highest maternal ultra-processed food consumption compared with the lowest consumption group.

This was an observational study, so cannot establish cause and the researchers acknowledged several limitations of their work. However, the study used data from large ongoing studies with detailed dietary assessments over a relatively long period, and analysis produced consistent associations, suggesting that the results are robust.

They said it was not immediately clear what may be behind the link between a mother’s consumption of ultra-processed food and child obesity, and called for further investigation.

“Although the underlying pathways of our findings have not yet been fully elucidated and remain beyond the scope of this investigation, maternal diet during child-rearing is likely to shape offspring’s diet and lifestyle choices, which subsequently exert a profound impact on their risk of overweight or obesity,” they wrote.

“Our results showed that the association between maternal ultra-processed food intake during the child rearing period and offspring risk of overweight or obesity was independent of offspring’s lifestyle risk factors. This finding indicates that there may be other pathways through which maternal ultra-processed food intake may influence childhood overweight risk; for example, long-term in utero imprinting and the presence of uncharacterised gene by environment factors.”