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Saul posted a topic in CR PracticeHigh-fat diet cuts brain’s food brake IN SECTION: BODY & BRAIN Mouse study hints at neural changes related to overeating BY LAURA SANDERS A gut-busting diet may set the brain up for more of the same. After mice ate fatty food for just two weeks, cells in their brains that send a “stop eating” signal were quieter than those in mice that didn’t eat high-fat chow, researchers report in the June 28 Science. Food is key to survival, which may be why the brain has built-in redundancy — a multitude of overlapping systems to make sure animals eat enough. Neuroscientist Garret Stuber of the University of Washington in Seattle investigated one area known to be involved in eating. Called the lateral hypothalamus, this brain structure contains a large number of diverse nerve cells. Stuber and colleagues looked at gene behavior in single cells there and found that one group, called glutamatergic nerve cells, showed particularly big changes in which genes were active when the team compared lean mice with obese mice. Earlier work suggested that glutamatergic cells act like a brake on feeding: When the cells were artificially blocked from firing signals, mice ate more food and gained more weight. But it wasn’t clear how these cells behave over a more natural shift from leanness to obesity. “Obesity doesn’t just happen overnight,” says Stuber, who conducted some of the work while at the University of North Carolina at Chapel Hill. To study that transition, the researchers fed mice high-fat mouse chow and periodically checked the glutamatergic cells’ ability to fire signals. Two weeks into the binge, even before mice plumped up, the nerve cells showed more sluggish activity, both in their spontaneous behavior and when an animal was given a sip of sweet liquid. That reduction continued as the mice grew larger, for up to 12 weeks in some cases. The results imply that “these cells’ decreased activity is removing the brake on feeding and obesity,” says neuroscientist Stephanie Borgland of the University of Calgary in Canada, who wrote a related commentary in the same issue of Science. The researchers don’t know whether these cells would regain their normal behavior if the mice stopped eating highfat food and shed weight. And it’s hard to say whether similar appetite-suppressing nerve cells are at work in people.