Saccharine or sucrose in water is more attractive to rats than cocaine

PLoS ONE: Intense Sweetness Surpasses Cocaine Reward

In a scholarly publication, scientists divulged the results of a study done on rats where they could make an exclusive choice (9x/day) between highly sugar-sweetened water and intravenous cocaine injections. To their surprise, the rats chose the sugar-water over 80% of the time compared to cocaine. This was true of 'naive' rats who had no prior exposure to the substances, and also of cocaine-sensitized rats who had exhibited a prior addiction to cocaine. Even the cocaine-addicted rats chose the sugar-water over maximal levels of cocaine the vast majority of the time. Scientists conclude that refined sugar is a 'supernormal stimuli', making self-control difficult and possibly leading to addiction. The findings of sugar trumping cocaine seem to be counter to current theory on the physiology of cocaine addiction, indicating a possible need to revise the theory. The findings are also counter to previous studies done where monkeys who were offered cocaine or sweetened dry food opted for the cocaine. Possible explanations are that the sweetened dry food wasn't wet and therefore had drawbacks (e.g thirst inducing), that the food alternative wasn't sweet enough (or that there wasn't enough of it), or that there is a relevant biological gap between rats and primates. Lastly, scientists speculate that the easy availability of sweetened foods in modern society might act as a shield from the spread of other addictive drugs.