At the Fralin Biomedical Research Institute at VTC, researchers work out of a commercial kitchen preparing tempting snacks like chocolate chip cookies, animal crackers and fried eggs with hash browns. Community members are paid to eat and drink while scientists measure factors such as brain activity and blood glucose.
The DONNUT Lab — for DiFeliceantonio Neuropsychology of Nutrition Lab — explores food choice mechanisms by breaking down specific characteristics of foods in the modern diet to examine how they affect the body, the brain and the ways the two interact. The lab also studies how individual variations in response to food traits may increase or reduce the risk of disease.
Alex DiFeliceantonio, principal investigator and co-director of the Roanoke research institute’s Center for Health Behaviors Research, is also an assistant professor in the Department of Human Nutrition, Foods and Exercise at Virginia Tech. Her work focuses on how the gut communicates with the brain as food moves through the digestive system. About nine researchers and medical students work in the lab, along with six other collaborators and several student volunteers.
The modern food environment is packed with highly processed foods and artificial sweeteners, DiFeliceantonio said. Although the health risks of processed foods are well documented, the U.S. Dietary Guidelines Advisory Committee recently noted that little is known about the biological mechanisms behind those risks, DiFeliceantonio said. This research gap makes it difficult for regulatory agencies to issue strong dietary recommendations.
“In which ways are [foods] interacting with our bodies that might lead to these poor health outcomes? So that’s what we’re interested in at the DONNUT Lab,” she said.
DiFeliceantonio is an appetitive neuroscientist, meaning she studies the brain systems that drive appetite. She earned her Ph.D. at the University of Michigan, where she began by researching addictive drugs in rodents. However, she was more interested — and entertained — by feeding M&Ms to the rats.
“I got really interested in this idea: If we always think of drugs as something that is unnatural stimulus that leads to really intense motivation, but you know, sugar, really high fat, high sugar are also intensely motivating and they’re also pretty unnatural … I got really interested in the brain systems that govern this intense motivation for food,” DiFeliceantonio said.
Her research relies on community participation. The DONNUT Lab is currently running three studies, each needing 30 to 60 participants. Recruitment ads on social media and flyers around town invite people to take part. Depending on the study, participants may be paid to snack.
“Recruitment, it’s really the sole factor in the success of human subject, human participant research studies. We have to partner with the community, and we need them to come in and help us do this type of work. We can’t do it without members of the community,” DiFeliceantonio said.
Hot Pockets, sweet potatoes and sugary drinks
One study places participants in an MRI scanner, where they see a collection of professionally photographed food images. These foods, prepared in the lab, include a range of highly processed foods, like Hot Pockets, and minimally processed foods like a baked sweet potato. Researchers control for things like consistency and portion size.
Participants play a game where they bid on the different food items when shown the photos.
Researchers then track brain activation with the MRI scanner. At the end, participants get to eat one of the foods they bid on.
Another study focuses on how the body responds to artificial sweeteners and sugar. Participants drink beverages containing sugar, artificial sweeteners or a combination of both. Researchers collect blood samples through an IV line at different intervals, measuring glucose, insulin and other hormones that play a role in metabolic health.
A third study examines how nutrients drive behavior. Participants taste a variety of flavored beverages and discuss which ones they like or dislike. A few flavors are then paired with different types of sugars. Participants take those drinks home and consume them regularly for two weeks. When they return to the lab, they repeat the taste test, share their preferences and undergo another MRI scan to see how their brains respond to the flavors.
DiFeliceantonio said her team uses ingredient lists from commercially available drinks, like Gatorade G2, and remakes them in the lab.
“We take that recipe and then we kind of re-engineer it in the lab so that we know exactly what’s in it and we can manipulate the flavors that way,” she said. This also allows researchers to control the sweeteners that are used.
Over 70% of U.S. grocery store foods are ultra-processed
Food choice is at the center of DiFeliceantonio’s research. Some choices are made by individuals while others are shaped by factors outside their control, she said.
A study by Northeastern University’s Network Science Institute found that more than 70% of foods sold in U.S. grocery stores are ultra-processed.
Despite their prevalence, there isn’t enough research to guide decisions about which foods should be available in schools or to make strong recommendations to the public, DiFeliceantonio said.
Her goal is to uncover the mechanisms that drive food-choice behaviors. That mission led her to launch the DONNUT Lab in 2019. After pandemic-related shutdowns, the lab is now fully operational and actively recruiting participants.
DiFeliceantonio’s work is supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Diabetes and Digestive and Kidney Diseases, both of which are part of the National Institutes of Health.
Private donors also support the lab. An NIH-funded collaboration between three Virginia institutions, iTHRIVE, also provided financial support for the lab, but operations for this program ended on Wednesday.
