 One study suggests that artificial sweeteners may not fully activate the brain's "food reward pathways" as sugar does, stating that, because sweetener does not provide full satisfaction, the user may search for, and then eat, additional high-calorie foods leading to weight gain.According to one study, sucralose is digestible by a number of microorganisms and is broken down once released into the environment.However, measurements by the Swedish Environmental Research Institute have shown sewage treatment has little effect on sucralose, which is present in wastewater effluents at levels of several μg/l (ppb).