Professor Joseph Schroeder and his students Jamie Honohan, Becca Markson, Gabriela Lopez and Katrina Bantis of Connecticut College in New London found rats formed an equally strong association between the pleasurable effects of eating Oreos and a specific environment as they did between cocaine or morphine and a specific environment.
They also found that eating cookies activated more neurons in the brain's "pleasure center" than exposure to drugs of abuse.
"Our research supports the theory that high-fat/high-sugar foods stimulate the brain in the same way that drugs do," Schroeder said in a statement. "It may explain why some people can't resist these foods despite the fact that they know they are bad for them."
To test the addictiveness of Oreos, the researchers measured the association between "drug" and environment.
On one side of a maze, they would give hungry rats Oreos and on the other, they would give them a control -- in this case, rice cakes.
Then, they would give the rats the option of spending time on either side of the maze and measure how long they would spend on the side where they were typically fed Oreos.
"Just like humans, rats don't seem to get much pleasure out of eating rice cakes," Schroeder added.
The researchers compared the results of the Oreo and rice cake test with results from rats that were given an injection of cocaine or morphine on one side of the maze and a shot of saline on the other.
The study showed rats conditioned with Oreos spent as much time on the "drug" side of the maze as the rats conditioned with cocaine or morphine.
The researchers measured for neuronal activity on the brain's pleasure center -- or how many cells were turned on in a specific region of the brain in response to the drugs or Oreos, Schroeder said.
The Oreos activated significantly more neurons than cocaine or morphine, the study said.
"This correlated well with our behavioral results and lends support to the hypothesis that high-fat/ high-sugar foods are addictive," said Schroeder.
Schroeder is scheduled to present the findings next month at the Society for Neuroscience conference in San Diego.