What do you think is more addictive: sugar or cocaine? Magalie Lenoir and her colleagues at the University Bordeaux in France have run an empirical study to find out.


They began with the supposition that, while highly refined sugars, corn syrup, and artificial sweeteners are relative newcomers in our diets, they are now ubiquitous. Overconsumption of diets rich in sugars contributes (along with other factors) drives the current obesity and type 2 diabetes epidemics.


Consumption of sugar-dense foods and beverages is motivated by the pleasure of sweet taste, and is often colloquially compared to drug addiction (as in, “I’m absolutely addicted to mochas!”). While there are many biological similarities between sweetened diets and addictive drugs, the addictive potential of sugar compared to drugs is unknown.


Until now. The Lenoir study found that when lab rats were free to choose between water sweetened with saccharin–an intense calorie-free sweetener–and cocaine–a highly addictive and harmful substance–the large majority of the animals (94%) preferred the saccharin. This preference was found to hold when saccharin was replaced with sucrose, a natural sugar. Finally, the preference for sweeteners could not be overwhelmed by increased doses of cocaine; this preference was observed despite cocaine intoxication, sensitization, and escalation–the hallmarks of drug addiction.


The findings clearly demonstrate that intense sweetness can surpass cocaine as a reward, even in drug-sensitized and addicted individuals. The researchers speculate that the addictive potential of intense sweetness results from an inborn hypersensitivity to sweet taste. In most mammals, including humans, sweet receptors evolved in ancestral environments poor in sugars. Our hunter-gatherer ancestors also found that foods that tasted sweet were less likely to be toxic. The taste receptors of modern Homo sapiens are not adapted to high concentrations of sugars and artificial sweeteners. The over-stimulation of these receptors by the sugar-rich diets now widely available in modern societies can generate a high-level reward signal in the brain, overriding natural self-control mechanisms and leading to addiction.


What does all this mean? When people say, “I’m absolutely addicted to mochas” (or whatever their super-sweet beverage of choice may be), they may be stating their case more clearly than they know. Chances are they are addicted, and kicking the super-sweet habit may well pose just as great a challenge as breaking any serious drug addiction.