Study Reveals Calorie-Free Sweeteners May Confuse Brain's Appetite Signals - Video

Compared to sugar, consuming sucralose a widely used sugar substitute increases activity in the hypothalamus, a brain region that regulates appetite and body weight, according to a new USC study. Sucralose also changes how the hypothalamus communicates with other brain regions, including those involved in motivation. The study was published in the journal Nature Metabolism.

The study included 75 participants, about evenly split between male and female and weight status (healthy weight, overweight or obese). On three separate visits, each participant was tested with sucralose, sugar or water, allowing the researchers to look for differences both within and between individuals.

The researchers tested how 75 participants responded after consuming water, a drink sweetened with sucralose or a drink sweetened with regular sugar. They collected functional magnetic resonance imaging (MRI) brain scans, blood samples and hunger ratings before and after participants consumed the drink. Sucralose increased hunger and activity in the hypothalamus, especially in people with obesity. It also changed the way the hypothalamus communicated with other brain regions. Unlike sugar, sucralose did not increase blood levels of certain hormones that create a feeling of fullness.

The findings show how sucralose confuses the brain by providing a sweet taste without the expected caloric energy

Ref: Chakravartti, S.P., Jann, K., Veit, R. et al. Non-caloric sweetener effects on brain appetite regulation in individuals across varying body weights. Nat Metab 7, 574–585 (2025). https://doi.org/10.1038/s42255-025-01227-8