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Food, herbs & supplements · health · gut · Emerging
Ultraprocessed Meals Trigger Bigger Insulin And Brain Responses In Adults
57 healthy-weight adultsCrossover designNutrient-matched mealsInsulin response differedBrain response differed
A study published October 5, 2026 in Nature Metabolism reports that ultraprocessed meals trigger bigger insulin and energy-use responses than nutritionally matched whole-food meals, even when calories and macronutrients are the same.
The randomized, controlled, crossover study followed 57 healthy-weight adults who each ate a nutritionally matched ultraprocessed food (UPF) meal and a non-UPF meal on separate occasions, so every participant served as their own comparison. The researchers report that the UPF meal produced a greater insulin response and a greater energy response than the non-UPF meal, along with reduced carbohydrate oxidation, the rate at which the body burns carbs for fuel, compared with the non-UPF meal. The authors found that differences in peak carbohydrate oxidation between the two meals were associated with activation in the striatum, a brain region involved in reward and motivation, during exposure to food cues. Subjective ratings of how much participants valued the food did not differ between the two meal types, but brain activity tied to that food valuation ran in opposite directions: positive for the non-UPF meal and negative for the UPF meal in the visual cortex and the striatum.
The authors state that these results point to food processing affecting post-ingestive metabolism and brain response through mechanisms beyond calories and macronutrients alone. Insulin is the hormone that moves sugar out of the blood and into cells, and how quickly and how much insulin rises after a meal affects hunger and fat storage signals; the brain's reward circuitry, including the striatum and visual cortex, helps determine how appealing a food feels and how much a person wants to eat it again.
UPF meals evoke greater insulinaemic and energetic responses, with attenuated carbohydrate oxidation relative to non-UPF meals
Data Panel
- Who
- 57 healthy-weight adults
- Design
- Randomized, controlled, crossover study; each participant consumed a nutrient-matched ultraprocessed meal and a non-ultraprocessed meal on separate occasions
- Dose
- One nutritionally matched ultraprocessed meal and one non-ultraprocessed meal per participant, compared within-person
- Primary result
- Ultraprocessed meals produced greater insulin and energy responses and lower carbohydrate oxidation than non-ultraprocessed meals; exact numeric values not reported in the abstract
- Secondary
- Differences in peak carbohydrate oxidation between meals were linked to striatal brain activation to food cues; brain responses tied to food valuation were positive for non-UPF and negative for UPF in the visual cortex and striatum, even though subjective food value ratings did not differ
- Funding / conflicts
- Funders listed in the journal record: U.S. Department of Health & Human Services | NIH | National Institute of Diabetes and Digestive and Kidney Diseases, National Science Foundation. Conflicts not reported in the abstract.
The published record is an abstract, and exact numeric values for the insulin, energy and carbohydrate-oxidation differences were not reported in it, so the size of these effects is not available. The study was conducted in healthy-weight adults over a short, single-meal comparison, which does not establish what happens with repeated exposure or in people who are overweight or have metabolic disease.
Dr. Axe's Take
This finding stands out to me because it shows two meals can match on paper, same calories, same carbs, same protein, and still produce different insulin spikes and different brain reward signals depending on how processed they are. Calories are not interchangeable once you account for how a food is made. That is exactly what this data shows: processing itself appears to change how the body handles a meal, separate from the nutrition label. My practical takeaway: build meals around whole foods, pasture-raised protein, vegetables, healthy fats, to keep insulin and brain-reward response stable. This week, swap one ultraprocessed staple for a whole-food version and notice how your hunger feels hours later.
— Dr. Axe