Your brain's reward system knows the difference between artificial sweeteners and sugar, suggests a new study in mice. The study's researchers, from the Yale University School of Medicine, noted that the finding, if applicable to humans, could explain why obesity rates continue to rise even with the arrival of diet drinks in the marketplace.
Published in The Journal of Physiology, the study shows that a signal known to play a role in regulation of dopamine (the reward-signaling chemical in the brain) only arises when sugar is broken down.
"According to the data, when we apply substances that interfere with a critical step of the 'sugar-to-energy pathway', the interest of the animals in consuming artificial sweetener decreases significantly, along with important reductions in brain dopamine levels," study researcher Ivan de Araujo, a professor at the university, explained in a statement.
"This is verified by the fact that when hungry mice -- who thus have low sugar levels -- are given a choice between artificial sweeteners and sugars, they are more likely to completely switch their preferences towards sugars even if the artificial sweetener is much sweeter than the sugar solution."
Even though the study was conducted in mice, Araujo said that the findings likely also apply to humans, and suggest that when people eat low or zero-calorie, artificially sweetened foods when they're hungry or tired, they may have an increased risk of consuming more calories later on.
The new findings fall into line with effects experts suspect diet products have on the brain. Nicole Avena, Ph.D., a sugar addiction researcher and assistant professor in the College of Medicine at the University of Florida, previously told HuffPost that while artificial sweeteners may be giving the brain satisfaction from sweet in the short term, that may not be the case in the long term. .
"If you're consuming beverages without calories and [you're] not getting fullness from sugar-sweetened beverages, you could be priming the brain to want to eat more," she told HuffPost. "That's one of the limitations of artificial sweeteners: In the long term, it could stimulate appetite, versus provide a benefit in the sense they're reducing calorie intake ... Over time, it's not helping the brain get over wanting sugar."
Weight gain has been linked in research with diet soda consumption, but experts have not been able to definitively pinpoint whether obese people choose to drink diet drinks in an effort to lose weight, or if the diet drinks are actually causing the weight gain.