Parents have long suspected that chips, soda and packaged snacks are not great for kids. Now a brain-imaging study suggests ultra-processed foods and children may be linked in a deeper way: kids who ate more of them showed a stronger reward response in the brain to pictures of food, and they gained more body fat over the following year. Here is what the study found, what it cannot prove, and simple steps for busy families.
What the Study Found
Researchers at the Keck School of Medicine of USC, in work partly funded by the National Institutes of Health, followed 46 children aged 7 to 10 who had a healthy weight at the start. The results appear in JAMA Network Open (2026; 9(10):e2640252), and a ScienceDaily summary lays out the key points.
- Children who ate more ultra-processed foods showed a stronger response in the dorsal striatum, a brain region involved in reward and habit, when shown pictures of food.
- Higher ultra-processed food intake was linked to greater gains in BMI and body fat over one year.
- When the researchers accounted for the brain response, the link between ultra-processed food and BMI weakened by 31%, and the link with body fat weakened by 44%.
That last point hints that the brain’s reaction to food may be part of the path from snack habits to weight gain, though the study cannot prove that on its own.
What Counts as Ultra-Processed?
Ultra-processed foods are industrial products made mostly from extracted ingredients and additives. Think sugary cereals, packaged cookies, sodas, chips, instant noodles and many frozen nuggets. According to the summary, about 67% of calories in the diets of U.S. children come from these foods.
| Often ultra-processed | Usually a better swap |
|---|---|
| Sugary breakfast cereal | Oatmeal with fruit |
| Flavored fruit snacks | Fresh or frozen fruit |
| Packaged cookies | Plain yogurt with berries |
| Chips | Popcorn made at home, nuts (age-appropriate) |
| Soda and sweet drinks | Water or milk |
Note on nuts and popcorn: both are choking risks for young children, and we covered the topic in our toy and choking safety guide for parents. Always match foods to your child’s age.
Important Limits
Parents should not panic. Several caveats apply:
- It is observational. The study shows links, not cause and effect.
- The sample is small. Forty-six children is far too few to represent all kids.
- One year is short. Longer studies are needed.
- Weight is not the whole story. BMI is a rough tool, and children’s growth varies.
The finding is best seen as a clue for future research, one that fits with broader advice to eat more whole foods.
Why Kids’ Brains Might Be Especially Sensitive
Children’s reward systems are still developing, and the habits formed in childhood often continue into adulthood. Foods engineered to be crunchy, sweet and salty at once can be very appealing. That is not a parenting failure; it is food marketing working as designed. Understanding it can help families make small changes without guilt.
Five Realistic Steps for Families
- Change one meal at a time. Start with breakfast or after-school snacks, not the whole pantry.
- Keep healthy options visible. A bowl of fruit on the counter wins more often than a hidden drawer.
- Read the first ingredients. A long list of unfamiliar additives is a signal to look for a simpler option.
- Cook together. Kids who help make food are often more willing to eat it.
- Don’t ban treats. Rigid bans can backfire. Aim for treats that are occasional, not daily staples.
When to Talk to a Pediatrician
This is general information, not medical advice. If you are worried about your child’s weight, picky eating or growth, ask your pediatrician or a registered dietitian. Avoid putting a child on a restrictive diet without professional guidance.
The Bottom Line
This small study adds to evidence that what kids eat shapes both their bodies and their brains’ responses to food. You do not need a perfect pantry; you need a few steady swaps. Stay tuned to USA One News for more family health coverage, and read the full summary of the study.
