Kristen Bell and Dax Shepard are determined to set a good example for their children. The celebrity duo – who have daughters Lincoln, 11, and Delta, nine – are keen to ensure their kids eat healthily and learn from the example of their parents. Dax, 49 – who has a degree in anthropology – told E! News: “Anthropologically speaking, we crave sugar because it was so scarce throughout history and because nothing that’s ever been poisonous has tasted really sweet. “But the reality is, it doesn’t make us feel good. So we talk about a lot about the outcome. And that’s also where movement steps into t…