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 new USC research. Sucralose also changes how the hypothalamus communicates with other brain regions, including those involved in motivation. The study was just published in the journal Nature Metabolism. 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 (fMRI) 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 and suggest that sucralose could impact cravings or eating behavior.