In a study involving healthy adults, researchers at Virginia Tech's Fralin Biomedical Research Institute found that meals with identical calorie and nutrient profiles, but differing in processing levels, resulted in different metabolic responses and brain activity. Neuroscientist Alex DiFeliceantonio and researcher Zach Hutelin led the study, which was published in Nature Metabolism this month.
The research aimed to explore whether food processing itself influences bodily responses. The findings revealed that ultraprocessed meals led to higher insulin release and increased energy expenditure while reducing carbohydrate usage for fuel. Additionally, the brain's reward system exhibited different responses to the two meal types.
Ultraprocessed foods constitute over half of the average American's daily caloric intake, and their consumption has been linked to various health issues, including obesity and Type 2 diabetes. DiFeliceantonio noted that while ultraprocessed foods are often high in fat and sugar, the study sought to isolate the effects of processing by controlling for these factors.
The study involved 57 healthy adults aged 18 to 45, with 32 participants completing both brain imaging and metabolic sessions. Participants consumed both minimally and highly processed meals, which were nutritionally matched to within 1% for carbohydrates, fats, proteins, calories, water, and salt. The highly processed meal included items such as a peanut butter and jelly sandwich and instant mashed potatoes, while the minimally processed meal consisted of a banana, cheese, and egg.
After fasting overnight, participants were tested in a metabolic chamber to measure energy expenditure and metabolism. Blood samples were taken before and after the meals to assess metabolic effects. Results indicated that the ultraprocessed meal resulted in a significantly higher insulin response and prolonged elevated blood sugar levels.
On a separate day, participants underwent functional MRI while viewing images of both meal types. The scans showed that the brain's responses to food cues were linked to the metabolic differences observed after consuming the meals. Although participants did not express a preference for either meal type in terms of willingness to pay, the study suggests that processing may influence both metabolic and brain responses to food.
DiFeliceantonio expressed interest in further research to explore different populations, meal sizes, and other factors that may contribute to these findings. The study was funded by a National Institutes of Health grant and a National Science Foundation fellowship.