Researchers Kyle Burger and Eric Stice of the Oregon Research Institute in Eugene tested whether eating ice cream very often would lead the brain to require more and more of it before sending signals that it's an enjoyable treat.
They surveyed 151 adolescents about their food cravings, and then scanned their brains while showing them images of a chocolate milkshake to determine how strong their cravings were. The researchers also measured brain activity when the subjects drank a tasteless liquid as a comparison. The teenagers were then fed actual milkshakes.
The participants who reported eating more ice cream over the previous two weeks enjoyed the shakes less -- at least according to the brain scans. The scans showed less activity in the area of the brain associated with reward.
"We believe that means the more an individual is consuming a high-fat, high-sugar and high-energy food, they develop a tolerance of it in a similar fashion that you see happening with drug addiction or alcohol addition," said Burger.
All the teens in the study were a healthy weight, and Burger said that suggests the changes in the brain are happening well before obesity sets in.
And the differences in brain activity also seem only to be associated with ice cream -- not other unhealthy foods like hamburgers, French fries or chocolate, although they don't yet know why.
While the effects of ice cream on the reward center of the brain seem to mimic those from drugs, Burger stressed that the study does not suggest that ice cream is addicting. That notion is a controversial one. Researchers are divided.
"I think ice cream use is like a drug in that it can become a strong reward for some people," said Dr. John Hughes, a professor of psychiatry at the University of Vermont in Burlington, who was not involved in the Oregon study. But, he added, "not all strong rewards are addictive."
True addiction, he said, is characterized by tolerance, withdrawal and loss of control over use. Ice cream does not have these effects on people.
Dr. Bob Gwyther, a professor of family medicine at the University of North Carolina School of Medicine in Chapel Hill, disagreed.
"Addicts exhibit behaviors that are harmful to themselves (and they know it), yet they continue to engage in the behavior," he said in an email to ABC News. "Picture someone standing in front of the refrigerator with a pint of ice cream, eating the entire carton, despite the fact that they are obese, diabetic or whatever."
Gwyther said many of his patients have tearfully described times when they gulped ice cream, knowing it was unhealthy but unable to stop their behavior.
Burger hopes the study can help uncover why some people head to the refrigerator or freezer for a reward while others engage in healthier behaviors, such as exercise, which could in turn explain how certain foods "contribute to the development and maintenance of obesity."