Summary:
A longitudinal neuroimaging study from the Keck School of Medicine of USC finds that children who consume larger proportions of ultra-processed foods (UPFs) show increased neural activation in the dorsal striatum when exposed to appetizing food cues. Published in JAMA Network Open, the study links this heightened reward responsivity to measurable increases in body mass index and body fat percentage one year later, revealing a plausible neurobiological pathway connecting processed diets to early weight gain.
Key Facts:
- Reward Circuit Hyper-Reactivity: Functional MRI scans showed that children with higher UPF intake exhibited significantly greater reward and motivation responses in the dorsal striatum when shown images of palatable foods.
- Brain Response Mediates Weight Gain: Dorsal striatum activation explained 31% of the link between UPF consumption and increased BMI, and 44% of the link with increased body fat over a one-year follow-up.
- Healthy-Weight Baseline Cohort: The study followed 46 children ages 7–10 who were all of healthy weight at baseline, indicating these neural changes appear before clinical excess weight develops.
Source: Keck School of Medicine of USC
Ultra-processed foods (UPFs) — including packaged breakfast cereals, chips, soda, commercially baked bread, and many instant snacks — now make up a large share of children’s daily calories in the United States, estimated at roughly two-thirds of intake. These industrially formulated products are engineered for high palatability, long shelf life, and convenience. They tend to be high in refined carbohydrates, saturated fats, and additives while low in fiber and essential micronutrients.
While prior public health research has associated UPF consumption with cardiovascular risk, insulin resistance, and pediatric obesity, the neurobiological processes linking these foods to metabolic outcomes in children have been less clear. This prospective study from USC addresses that gap by examining how habitual UPF intake affects the developing brain’s reward systems and how those neural effects relate to later changes in body composition.
Published in JAMA Network Open, the study reports that higher habitual intake of UPFs sensitizes the brain’s motivation circuits to food cues and predicts subsequent gains in body fat and waist circumference over the following year.
Mapping the Dorsal Striatum Under Food Cues
Researchers drew participants from the NIH-funded BrainChild study, a longitudinal effort investigating neurobiological pathways tied to diabetes and metabolic vulnerability in youth. The analysis included 46 children aged 7 to 10, all of whom were clinically healthy weight at enrollment. Starting from a healthy-weight baseline allowed the team to identify neural vulnerabilities that precede overweight or obesity.
At baseline each child completed functional magnetic resonance imaging (fMRI) while viewing photographs of appetizing foods (such as French fries and cookies) and matched non-food images. The investigators collected multiple 24-hour dietary recalls to estimate the percentage of daily calories from UPFs using the NOVA classification, and recorded body mass index (BMI), waist circumference, and body fat percentage by DEXA. All measures were reassessed approximately 12 months later.
Baseline fMRI scans showed a clear neural pattern: children with higher habitual UPF consumption had stronger blood-oxygen-level-dependent (BOLD) responses in the dorsal striatum when viewing food pictures. The dorsal striatum is a subcortical hub in dopamine-dependent circuits that support reward anticipation, habit formation, and motivated behavior.
“Children’s brains are still developing, habits are still forming and food preferences are still being made. It’s an important period where the brain is very sensitive to food and the food environment,” said senior author Kathleen A. Page, MD, professor of medicine and pediatrics and co-chief of the Division of Endocrinology and Diabetes at the Keck School of Medicine of USC. “We’re particularly interested in understanding these processes in children, because we believe that intervening early could make a real difference.”
The Neurobiological Driver of Weight Gain
Across the one-year follow-up, children who consumed more UPFs at baseline gained more waist circumference, showed greater increases in BMI, and had larger rises in body fat percentage. Mediation analyses indicated these associations were substantially channeled through reward circuitry: when researchers adjusted for the strength of dorsal striatum activation to food cues, the UPF–BMI association decreased by 31% and the UPF–body fat association decreased by 44%.
Those changes suggest dorsal striatal hyper-responsivity is not merely an incidental marker of diet but appears to act as a neurobiological mediator linking processed food consumption to adiposity gain during childhood.
“This study goes beyond just understanding that UPFs affect weight gain,” Page noted. “It actually gives us insight into the neurobiological underpinnings by which these foods may be linked to body composition over time.”
Addressing the Broader Food Environment
The authors stress that UPFs are heavily marketed, inexpensive, and widely available, so responsibility for healthier diets cannot fall solely on children or on families. Highly engineered foods can undermine homeostatic satiety signaling and condition developing neural circuits to crave hyper-palatable calories.
“Changing the food environment to help people access healthier, more minimally processed foods is an important part of the solution,” Page emphasized.
Because this study is observational, the research team plans randomized dietary intervention trials to test causality. Future work will assign children with high baseline UPF intake to minimally processed dietary plans to determine whether reward-circuit hyper-reactivity can be reduced and whether such neurobehavioral changes translate into lower long-term obesity risk.
Funding: Supported by an American Diabetes Association Pathway Accelerator Award [1-14-ACE-36]; and the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH [R01DK116858, R01DK134079]. The REDCap database used for this study was supported by the Southern California Clinical and Translational Science Institute [NIH UL1TR001855].
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by staff.
About this neurodevelopmental research:
- Media Contact: Laura LeBlanc
- Source: USC
- Image Credit: Image credited to Neuroscience News
- Original Research (Open Access): JAMA Network Open (Oct 1, 2026). Title: “Ultraprocessed Food Intake, Striatal Response to Food Cues, and Adiposity Gain in Children.” Authors: Jasmin M. Alves, Ella Morgan, Brendan Angelo, Kianna Le, Jared Smith, Ting Chow, Kay Jann, Anny H. Xiang, and Kathleen A. Page.
- DOI: 10.1001/jamanetworkopen.2026.40252
Abstract
Ultraprocessed Food Intake, Striatal Response to Food Cues, and Adiposity Gain in Children
Importance
Preclinical data suggest that ultra-processed foods (UPFs) may amplify dopaminergic signaling in the striatum and reinforce intake. Whether routine UPF consumption relates to striatal responses to food cues and predicts adiposity gain in children has been unclear.
Objective
To evaluate associations between habitual UPF intake, striatal responses to food cues, and one-year changes in adiposity in children.
Design, Setting, and Participants
This prospective cohort included children of healthy weight enrolled in the BrainChild study. Baseline assessments (MRI, dietary recalls, and adiposity measures) were completed between April 11, 2015, and June 28, 2024; follow-up adiposity assessments occurred approximately one year later.
Exposure
Habitual UPF intake, defined as the percentage of total energy from UPFs based on multiple 24-hour dietary recalls and classified using NOVA.
Main Outcomes and Measures
BOLD responses to food cues in the dorsal and ventral striatum during fMRI, and one-year changes in BMI, body fat percentage, and waist circumference. Analyses used linear regression adjusted for age, sex, baseline BMI, and total caloric intake.
Results
Among 46 healthy-weight children (mean age 8.7 years; 57% female), higher habitual UPF consumption was associated with greater dorsal striatal BOLD responses to food cues but not with ventral striatal responses. Greater dorsal striatal responsivity was linked to one-year increases in BMI and body fat percentage. Baseline UPF intake was associated with increased waist circumference at one year. Including dorsal striatal responsivity in models attenuated the UPF associations with BMI and body fat gain.
Conclusions and Relevance
In this cohort of children of healthy weight, higher habitual UPF intake correlated with increased dorsal striatal responses to food cues and with prospective adiposity gains. These findings suggest that reward-related brain responses may play a role in the relationship between UPF consumption and childhood adiposity increases.