Fiber works its weight loss magic in multiple ways. It helps you feel fuller, longer so eating fiber-rich foods is the dieting equivalent of working smarter, not harder. Plus, fiber takes a long time to digest, so fiber-rich foods don’t cause spikes in blood sugar that can send your insulin levels soaring. On the other hand, when you eat the so-called bad carbs (the refined or sugary ones that lack fiber), you may wind up with an insulin response that promotes fat storage. The takeaway: More fiber equals less fat storage.