Sugar addiction is more than a trite expression people use to describe their sweet tooth. A pattern of fasting and overloading on sugary foods may foster dependence, according to a study published in Obesity Research.
"People with a genetic predisposition for addiction can become overly dependent on sugar, particularly if they periodically stop eating and then binge," warns Bart Hoebel, Ph.D., a psychologist at Princeton University who led the study. "Laboratory experiments with rats showed that signs of sugar dependence developed over the course of 10 days. This suggests that it does not take long before the starve-binge behavior catches up with animals, making them dependent."
Earlier research found that this pattern sensitizes both dopamine and opioid receptors in rats. A cycle of deprivation and excessive sugar intake reinforces bingeing.
Abstinence also triggers withdrawal symptoms that resemble those of drug addiction, such as anxiety, chattering teeth and tremors. The taste of sugar makes the brain release natural opioids, and the bingeing causes dopamine release.
"There is something about this combination of heightened opioid and dopamine responses in the brain that leads to dependency," explains Hoebel. "Without these neurotransmitters, the animal begins to feel anxious and wants to eat sweet food again."
The rats exhibited behavioral changes even when sugar was replaced with the artificial sweetener saccharin. "It appears to be the sweetness, more than the calories, that fuels sugar dependence," says Hoebel.
Although researchers still don't understand how people can curb their sugar cravings, they do know that withdrawal symptoms and dips in dopamine levels aren't evident when meals are moderate and regularly scheduled.