Do calorie-free sweeteners cause appetite disruption?

A new study from the Keck School of Medicine at the University of Southern California reveals that calorie-free sweeteners, like sucralose, can disrupt brain signals related to appetite and potentially increase cravings, particularly in people with obesity.

Published in Nature Metabolism, the study shows sucralose activates the hypothalamus, a region of the brain that helps regulate hunger and body weight. While it mimics the sweetness of sugar, sucralose does not provide the expected caloric energy. This mismatch may lead to an increase in appetite and overeating, especially over time.

“But are these substances actually helpful for regulating body weight? What happens in the body and brain when we consume then, and do the effects differ from one person to the next?” said the study’s corresponding author, Kathleen Alanna Page, director of the USC Diabetes and Obesity Research Institute and co-chief of the Division of Endocrinology and Diabetes.

The study involved 75 participants, who consumed either water, sugar-sweetened beverages, or sucralose-sweetened drinks. Using brain imaging techniques and blood samples, the researchers observed participants who drank sucralose-sweetened beverages had heightened activity in the hypothalamus, signaling increased hunger. This effect was particularly pronounced in individuals with obesity, who did not experience the same fullness response that normally follows the consumption of sugar.

According to the study, unlike sugar, sucralose does not trigger the release of hormones that signal satiety to the brain, which might explain why people may continue to feel hungry even after consuming calorie-free sweeteners.

Page noted the discrepancy between sweetness and the absence of calories could be responsible for disrupting the brain's normal signals. 

"If your body is expecting a calorie because of the sweetness, but doesn’t get the calorie it’s expecting, that could change the way the brain is primed to crave those substances over time,” she explained.

The study also found differences in how men and women responded to sucralose. Female participants showed more significant changes in brain activity compared to male participants, suggesting that gender may play a role in how artificial sweeteners impact hunger signals.

Researchers are now planning further studies to examine how calorie-free sweeteners affect children and adolescents, who tend to consume larger quantities of these products.

This study raises important questions about the long-term health effects of artificial sweeteners on appetite regulation and weight management, particularly for individuals with obesity.