If you think you are addicted to sweets, you could be right.
Researchers at Connecticut College performed an interesting set of experiments in rats using America’s favorite cookie, the Oreo. In their model, the scientists placed rats in a maze with two possible exits, one contained a rice cake and the other held an Oreo cookie. Not surprisingly, rats spent significantly more time on the Oreo cookie side than pursuing the rice cake. However, undergraduate neuroscience student Jamie Honohan and peers added another interesting element to the experiment. They compared rats injected with moderate doses of morphine or cocaine—two highly addictive drugs—against a saline injection. Interestingly, rats spent as much time on the drug side compared to saline as they spent on the Oreo side vs. rice cakes. By this measure, rats found Oreo cookies as pleasurable and rewarding as cocaine or morphine.
Perhaps the most interesting finding of the research thus far was when researchers took a closer look at the brains of these animals. They used immunohistochemistry to measure the levels of c-fos in the brain’s pleasure center, the nucleus accumbens. Quite astonishingly, rats with access to Oreos had higher levels of c-fos in the nucleus accumbens than rats injected with addictive drugs. In other words, from a neurological perspective, there was greater neuronal activation of pleasure centers with a cookie than a street drug.
This work supports and extends what other laboratories have reported.1 Sugar intake releases opioids and dopamine—neurochemicals that create pleasurable sensations. While sugar is needed for survival, foods that are ultrahigh in sugar seem to create a chemical “dependency” i.e., eliciting signs of tolerance (needing higher levels of sugar), persistent motivation to seek out high sugar foods, and symptoms of withdrawal when high sugar foods are removed.2
This research has rather profound implications for those trying to find ways to curb obesity. It shows rather elegantly that high sugar/high fat foods can be as pleasurable as addictive drugs. It also suggests that this type of high sugar/high fat foods have the capacity to be as addictive as cocaine and morphine.
1. Avena NM, Rada P, Hoebel BG. Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev.
2. Avena NM, Hoebel BG. A diet promoting sugar dependency causes behavioral cross-sensitization to a low dose of amphetamine. Neuroscience. 2003;122(1):17-20.