We start the new year by checking in on one of the longest-running debates in addiction science: Is there such a thing as food addiction? Is there such a thing as eating addiction? How are they different from each other? How are they different from other substance use disorders? How are they different from other behavioral disorders?

It seems obvious that some foods can become addictive, and that those foods are mostly ultra-processed foods (UPFs), high in fat and sugar content. What seems obvious, however, is difficult to prove.

The publication Scientific American, or SciAm, ended 2025 by seeking an answer to the question of whether UPFs can be addictive. They interviewed Alexandra DiFeliceantonio, an “appetitive neuroscientist” with a lab at Virginia Tech who studies the brain and eating behavior. Dr. DiFeliceantonio was a postdoc at the Max Planck Institute for Metabolism Research in Germany, where she “examined the role of post-ingestive dopamine signaling in eating behavior and food choices.”

Dr. DiFeliceantonio recently conducted a set of experiments to gauge the impact of an ultraprocessed diet on subsequent eating behavior. Participants between the ages of 18 and 25 consumed either a diet with 81% UPFs or zero UPFs for two straight weeks. After a four-week “wash out,” they switched, with the same people spending two weeks on the opposite regime.

An interesting age divide appeared in the results. Older participants aged 21-25 showed no increase in consumption after two weeks on the high UPF diet. Younger participants aged 18-21 showed increased food consumption.

In another test, participants who were not hungry were given the choice of eating snacks or using their smartphones. Again, the younger cohort who had undergone two weeks of a high UPF diet went for the snacks. Dr. DiFeliceantonio summarizes:

The study didn’t directly measure addictive behavior, but it demonstrates how ultraprocessed food can lead to behavior change.

As to why UPFs are addictive, Dr. DiFeliceantonio says it is because they trigger the reward system. “All addictive drugs increase dopamine in the striatum,” a brain region involved in reward processing. “If you infuse sugar and fat into the oral cavity of an animal, you see an increase in dopamine. If you infuse these things directly into the gut, you also see increases in dopamine,” Dr. DiFeliceantonio told SciAm.

This doesn’t happen with broccoli, she says. UPFs act on multiple reward levers. They are scientifically engineered to increase palatability, mouth feel, hand feel, smell triggers, and taste bud activation. UPFs are often packaged in a way to encourage “mindless snacking.”

As to whether food addiction is a substance use disorder, Dr. DiFeliceantonio points to the Yale Food Addiction Scale (YFAS), a widely-used measure of food addiction that is modeled after the criteria for substance use disorders in the Diagnostic and Statistical Manual of Mental Illnesses (DSM-5). Interestingly, the YFAS says it measures “addictive-like eating behavior,” also known as eating addiction, a behavioral addiction, not a substance use disorder.

The YAFS is a 25-item diagnostic in use since 2009 that attempts to assess such things as:

• lack of control over consumption
• a persistent desire to reduce overeating
• repeated unsuccessful attempts to reduce overeating
• symptoms of withdrawal when resisting eating
• “clinically significant impairment” due to overeating

Dr. DiFeliceantonio tells SciAm that 12% of people tested in large population studies with YFAS experience food addiction. Roughly 40% of Americans are considered obese, according to estimates from the Centers for Disease Control (CDC).

As far as treating food addiction, Dr. DiFeliceantonio is impressed with the early results using GLP-1 drugs to reduce “food noise.” She hopes for restrictions on the marketing of UPFs, especially to children. Her lab is now looking for a genetic predisposition toward eating addiction, such as has been found with alcohol use disorder. 

Written by Steve O’Keefe. First published January 7, 2026.

Sources:

“Can Ultraprocessed Foods Be Addictive? A Neuroscientist Weighs In,” Scientific American, December 30, 2025.

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