Summary:
A longitudinal neuroimaging study from the Keck School of Medicine of USC reveals that children who consume higher amounts of ultra-processed foods (UPFs) exhibit heightened neural activation in the brain’s dorsal striatum when viewing appetizing food cues. Published in JAMA Network Open, the findings demonstrate that this elevated reward reactivity directly accounts for subsequent increases in body mass index and body fat percentage one year later, uncovering the neurobiological mechanism connecting processed diets to childhood obesity.
Key Facts:
- Reward Circuit Hyper-Reactivity: Functional MRI scans revealed that children consuming higher levels of UPFs show significantly stronger reward and motivation responses in the dorsal striatum when presented with images of appetizing foods.
- Brain Response Mediates Weight Gain: Heightened dorsal striatum activation accounted for 31% of the association between UPF intake and increased BMI, and 44% of the association with increased body fat percentage over a one-year follow-up.
- Healthy-Weight Baseline Cohort: The study tracked 46 children aged 7 to 10 who all began the study at a healthy weight, demonstrating that neural cue-reactivity changes emerge before the clinical onset of excess weight gain.
Source: Keck School of Medicine of USC
Ultra-processed foods (UPFs), such as packaged breakfast cereals, chips, soda, commercially baked bread, and instant processed snacks, dominate the modern dietary landscape, accounting for approximately 67% of daily caloric intake among children in the United States. Engineered for high palatability, shelf stability, and convenience, these industrially formulated products are typically dense in refined carbohydrates, saturated fats, and artificial additives, while depleted of dietary fiber and essential micronutrients.
While extensive public health research has tied UPF consumption to cardiovascular illness, insulin resistance, and pediatric obesity, the upstream neurobiological mechanisms driving these metabolic trajectories have remained poorly defined.
Now, a longitudinal investigation led by researchers at the Keck School of Medicine of USC identifies how ultra-processed foods reshape the developing brain’s reward architecture.
Publishing in the journal JAMA Network Open, the research team demonstrated that higher UPF intake sensitizes the brain’s motivation circuits to food cues, directly forecasting gains in body fat and waist circumference over the following year.
Mapping the Dorsal Striatum Under Food Cues
The study drew participants from the ongoing, NIH-funded BrainChild study, which examines neurobiological pathways underlying diabetes and metabolic vulnerability in youth. Researchers evaluated 46 children between the ages of 7 and 10. Crucially, all participants entered the study at a clinically healthy body weight, allowing scientists to monitor neural vulnerabilities before the development of overweight status or obesity.
At the start of the study, each child underwent functional magnetic resonance imaging (fMRI) while viewing photographs of appetizing foods (such as French fries and cookies) alongside non-food control images. The team systematically recorded dietary intakes, body mass index (BMI), waist circumference, and dual-energy X-ray absorptiometry (DEXA) body fat percentages, reassessing all metabolic and body composition parameters 12 months later.
The baseline scans revealed an unmistakable neural signature: children who regularly consumed higher quantities of UPFs exhibited markedly elevated blood-oxygen-level-dependent (BOLD) signals in the dorsal striatum when viewing food images. The dorsal striatum serves as a key subcortical hub in the dopamine-driven striatal network that governs reward anticipation, habit formation, and motivated action.
“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
Over the one-year follow-up, children with higher baseline UPF intake accumulated greater waist circumference, higher BMIs, and increased overall body fat percentage.
However, mediation analyses revealed that these metabolic outcomes were largely driven through the brain’s reward centers. When the investigators statistically controlled for the magnitude of dorsal striatum activation in response to food cues, the association between UPF intake and BMI increases weakened by 31%, while the association with body fat gains dropped by 44%.
These statistical shifts confirm that hyper-responsiveness in reward networks is not merely an incidental biomarker, but a primary neurobiological mediator linking ultra-processed diet consumption to excess weight gain in early development.
“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 emphasize that because UPFs are heavily marketed, cheap, and ubiquitous, the burden of dietary change cannot rest solely on pediatric self-control or family vigilance. Industrial formulations can override homeostatic satiety signaling, effectively conditioning children’s 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 the present findings are observational, the USC team is planning randomized dietary intervention trials to establish direct causality. In future work, children with high baseline UPF diets will receive structured, minimally processed nutritional plans to test whether reward-circuit hyper-reactivity can be dialed down and whether neurobehavioral reset translates into reduced long-term obesity risk.
Funding: This research was supported by an American Diabetes Association Pathway Accelerator Award [1-14-ACE-36]; the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (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 our staff.
About this neurodevelopmental research:
- Media Contact: Laura LeBlanc
- Source: USC
- Image Credit: Image credited to Neuroscience News
- Original Research is Open Access: JAMA Network Open (Oct 1, 2026). “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 studies suggest that ultraprocessed foods (UPFs) are associated with increased dopaminergic signaling in the striatum, reinforcing intake. Whether habitual UPF consumption is associated with striatal responses to food cues and subsequent adiposity gain in children is unknown.
Objective
To examine associations between habitual UPF intake, striatal responses to food cues, and 1-year adiposity changes in children.
Design, Setting, and Participants
This prospective cohort study included children of healthy weight who were participating in the longitudinal BrainChild study. Baseline assessments were completed between April 11, 2015, and June 28, 2024, and included brain magnetic resonance imaging (MRI), dietary recalls, and adiposity measurements. Additional follow-up assessments of adiposity were conducted 1 year later (April 18, 2016, to June 19, 2025).
Exposure
Habitual UPF intake, defined as the percentage of total energy intake from UPFs based on multiple 24-hour dietary recalls using the NOVA classification system.
Main Outcomes and Measures
Blood oxygenation level–dependent (BOLD) responses to food cues in the dorsal and ventral striatum during functional MRI and 1-year changes in body mass index (BMI), body fat percentage, and waist circumference. Associations were examined using linear regression models and adjusted for age, sex, baseline BMI, and total caloric intake, with regression coefficient (β) reported as per SD change in outcome with per SD change in the exposure variable.
Results
In 46 children of healthy weight (mean [SD] age, 8.7 [1.1] years; 26 [57%] female; baseline BMI range, 13.8-19.9; body fat percentage range, 12.7%-32.2%), higher habitual UPF consumption was associated with greater BOLD responses to food cues in the dorsal striatum (β = 0.34; 95% CI, 0.07-0.61) but not the ventral striatum (β = 0.16; 95% CI, −0.14 to 0.46). Greater dorsal striatal food cue responsivity was associated with 1-year increases in BMI (β = 0.32; 95% CI, 0.02-0.62) and body fat percentage (β = 0.44; 95% CI, 0.15-0.72). Baseline UPF intake was associated with a 1-year increase in waist circumference (β = 0.38; 95% CI, 0.11-0.66). Point estimates for associations between UPF intake and increases in BMI (β = 0.28; 95% CI, 0.00-0.57) and body fat percentage (β = 0.29; 95% CI, 0.00-0.57) were positive. Inclusion of dorsal striatal responsivity attenuated the UPF associations with 1-year change in BMI by 31% and with body fat percentage by 44%.
Conclusions and Relevance
In this cohort study of children of healthy weight, higher habitual UPF intake was associated with greater dorsal striatal responses to food cues and prospective increases in adiposity. These findings suggest that reward-related brain responses may be involved in associations between UPF consumption and adiposity gain during childhood.
