If you happen to be a Nabisco executive who is currently considering adding cocaine to Oreo cookies' long list of ingredients, here's some research that says you needn't bother.
Undergraduate researchers at Connecticut College have found that rats tend to behave toward the iconic cookies the same way they behave toward cocaine and morphine.
The researchers – a team of four undergrads led by Conn College neuroscience professor Joseph Schroeder – placed rats in a maze with Oreo cookies on one side and rice cakes on the other, measuring the amount of time the rats spent on each side.
You can guess which one the rats preferred. "Just like humans, rats don’t seem to get much pleasure out of eating [rice cakes]," said Dr. Schroeder, in a press release.
More surprising was just how much the rats craved the creme-filled cookies. Schroeder conducted a similar experiment, except that instead of tempting the rats with Oreos and rice cakes, he did so with injections of cocaine or morphine on one side, and saline injections on the other. It turns out that the rats spent as much time on the Oreo side of the maze in the Oreo experiments as they did on the drug side of the maze in the drug experiments.
"Our research supports the theory that high-fat/high-sugar foods stimulate the brain in the same way that drugs do," Schroeder said. "It may explain why some people can't resist these foods despite the fact that they know they are bad for them."
Most drugs are thought to work by hijacking the brain's pleasure center, the collection of neural structures that have evolved over millions of years to reinforce behavior that has tended to help pass genes on to the next generation. Research in recent decades suggests that sugars, fats, and salts tend to activate these same structures, sometimes resulting in behavior similar to that of drug addicts.
When the researchers measured stimulation in the rats' brains' pleasure centers, they found that the Oreos actually activated more neurons than cocaine or morphine.
"My research interests stemmed from a curiosity for studying human behavior and our motivations when it comes to food," said Jamie Honohan, the neuroscience major who designed the experiment. "We chose Oreos not only because they are America’s favorite cookie, and highly palatable to rats, but also because products containing high amounts of fat and sugar are heavily marketed in communities with lower socioeconomic statuses."
Rats, of course, don't always behave like humans, and it remains to be seen whether Oreos are as addictive to humans as they are to rats. But the researchers did note that, like many humans, the rats preferred the "twist and lick" method. “They would break it open and eat the middle first,” said Ms. Honohan.
The researchers' findings are to be presented next month at the Society for Neuroscience conference in San Diego, Calif.