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Brain responses to nutrients are severely impaired and not reversed by weight loss in humans with obesity: A randomized crossover study
Rodent eating behavior is regulated by post-ingestive nutritional signals to the brain, and disordered eating behavior and obesity have been linked to inadequate responses to these signals. In this study by van Galen et al. (2023), the authors conducted a single-blinded, randomized, controlled, crossover research in 30 healthy people (females N = 12, men N = 18) and 30 people who were obese (females N = 18, males N = 12). Observations were made on the impact of intragastric infusions of glucose, fat, and water (noncaloric isovolumetric control) firstly on striatal dopamine release and cerebral neuronal activity and the secondary endpoints of plasma hormones and glucose, caloric intake, and hunger scores. Imaging was performed following a 10% diet-induced weight loss to examine if the decreased responses in obese people might be partially reversible. Analysis of the results demonstrated that, in lean volunteers, intragastric glucose and lipid infusions resulted in nutrient-specific cerebral neuronal activity and striatal dopamine release, which were orosensory-independent and preference-independent. Participants that are obese, however, showed dramatically hampered brain reactions to nutrients post-ingestion. Finally, diet-induced weight loss was not found to repair the altered neuronal responses. The authors conclude that overeating and obesity may be caused by impaired neuronal responses to nutritional cues, and the high rate of weight gain following a successful weight reduction effort may be partially explained by continued resistance to post-ingestive food signals after significant weight loss. [NPID: Brain, diet, nutrition signals, obesity, neuronal response, weight loss]
Year: 2023
