Published Oct 29, 2026 | 9:30 AM ⚊ Updated Oct 29, 2026 | 9:30 AM
Children who consumed more UPFs showed heightened reward responses in the dorsal striatum.
Synopsis: A new study links higher ultra-processed food consumption in children to stronger brain reward responses and subsequent increases in body fat. In India, nutrition advocate Arun Gupta says the findings strengthen calls to restrict unhealthy food advertising to children. Researchers caution that the small observational study cannot establish causation.
Higher ultra-processed food (UPF) consumption is associated with stronger brain responses to images of appetising foods in children, which are in turn linked to increases in body fat over the following year, according to a new study published in JAMA Network Open.
The findings added to the debate over whether the formulation and marketing of highly processed foods could influence children’s eating habits, an issue that nutrition advocates in India have been pressing the government to address.
Researchers from the University of Southern California and Kaiser Permanente Southern California studied 46 children who were of healthy weight at the beginning of the study.
They found that children who obtained a greater proportion of their daily calories from UPFs showed stronger responses in the dorsal striatum, a brain region involved in reward, motivation, and habit formation, when viewing pictures of foods such as cookies and French fries.
Greater responses in this brain region were associated with increases in body mass index (BMI) and body fat percentage over one year. Higher UPF consumption was also associated with an increase in waist circumference.
For Dr Arun Gupta, convenor of Nutrition Advocacy in Public Interest (NAPi) and a co-author of the 2025 Lancet Series on Ultra-Processed Foods, the findings add to concerns about the influence of food products designed to be highly palatable and heavily marketed to Indian children.
“This study moves the debate from obesity to addiction,” Gupta said. “UPFs are not just making children fat, and they are changing the way their brains respond to food.”
He added that children who consumed more UPFs showed heightened reward responses in the dorsal striatum, which is involved in habit formation and reward-seeking.
However, the study did not establish that ultra-processed foods caused changes in brain function or that the children developed addictive eating behaviours. Its authors recommended larger studies to clarify the relationship between food consumption, brain responses and weight gain.
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The 46 children included in the study had a mean age of 8.7 years, and 57% were girls. At baseline, they obtained an average of 67.7% of their daily calories from UPFs.
Researchers assessed their diets through two 24-hour dietary recalls and measured BMI, body fat percentage, and waist circumference. They also used functional magnetic resonance imaging (fMRI) to measure brain responses as children viewed images of highly palatable foods alongside neutral objects.
Higher UPF consumption was associated with stronger responses in the dorsal striatum, even after the researchers accounted for age, sex, baseline BMI, total calorie intake, and maternal gestational diabetes status. No statistically significant association was found between UPF intake and responses in the ventral striatum, another region involved in reward processing.
The researchers then examined whether these brain responses were associated with subsequent changes in body composition. Greater dorsal striatal responses were associated with increases in BMI and body fat percentage at the one-year follow-up.
Higher UPF consumption was also associated with increased waist circumference. The associations between UPF intake and BMI and body fat percentage were positive, but their statistical significance was borderline.
When researchers accounted for dorsal striatal responses, the association between UPF intake and BMI gain weakened by 31%, while the association with body fat percentage gain weakened by 44%.
The authors said this pattern was consistent with a possible role for reward-related brain activity in the relationship between UPF consumption and increasing adiposity. They did not conduct a formal mediation analysis because the sample was too small.
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The findings come amid continuing calls by nutrition advocates in India for stronger restrictions on the promotion of foods high in fat, sugar and salt (HFSS), particularly advertisements that reach children.
NAPi has argued that children’s exposure to marketing for unhealthy foods needs to be treated as a public health concern rather than solely as a question of parental responsibility.
“The industry has engineered products that hijack the brain’s reward system in children as young as eight years old,” Gupta said.
He also criticised the use of cartoon characters, celebrity endorsements, promotional offers and health claims to market food products to children, arguing that these practices can shape food preferences and consumption patterns.
The US study did not examine food advertising, marketing exposure or the effects of particular promotional strategies. It therefore cannot establish that advertising caused the observed brain responses.
Nevertheless, NAPI argues that evidence on the relationship between UPF consumption and children’s responses to food cues strengthens the case for examining the wider food environment in which children make dietary choices.
The study’s senior author, Kathleen A Page, professor of medicine and paediatrics at the Keck School of Medicine of the University of Southern California, also emphasised the importance of the environment in shaping children’s diets.
“Changing the food environment to help people access healthier, more minimally processed foods is an important part of the solution,” Page said.
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NAPi has been pursuing changes to India’s advertising and journalistic guidelines to restrict the promotion of HFSS foods.
According to the organisation, it submitted proposed amendments to the Press Council of India’s Norms of Journalistic Conduct 2022, seeking to include HFSS foods among products whose advertising should be prohibited, alongside tobacco and alcohol.
The proposal sought to prohibit advertisements that directly or indirectly promote the production, sale or consumption of such foods.
NAPi said the Press Council informed it in May 2024 that the proposal did not fall within its purview and directed the organisation to the Union Ministry of Health and Family Welfare. In June 2025, the council sought the ministry’s specific comments, which NAPI said had not been received. The organisation said the council issued a reminder in 2026.
NAPi has also called for action on provisions in the National Multi-Sectoral Action Plan for Prevention and Control of Common Non-Communicable Diseases, 2017-2022, which included recommendations concerning restrictions on advertising HFSS foods.
The status of these proposals and the government’s response are separate from the findings of the new study. The research itself did not assess Indian food regulations or evaluate the impact of advertising restrictions.
The researchers also examined whether added sugar intake could account for the association between UPF consumption and brain responses.
Higher added sugar intake was not significantly associated with stronger responses in either the dorsal or ventral striatum. The association between UPF consumption and dorsal striatal responses was also no longer statistically significant after adjustment for added sugar.
The authors noted that UPFs often combine fats and carbohydrates in ways that can make them highly palatable. They said these characteristics could be relevant to understanding the relationship between dietary patterns and reward-related brain activity, although further research is needed.
The study has important limitations. It included only 46 children, assessed brain activity at a single time point, and relied on recalled dietary information. All participants were of healthy weight at baseline, limiting the extent to which the findings can be generalised to children with overweight or obesity.
(Edited by Majnu Babu).
