This new front-of-package nutrition label is designed to make us healthier

For more than a century, the U.S. government has tried to bring more transparency to food labels. It started in 1906, when the Pure Food and Drug Act cracked down on mislabeled ingredients and false health claims. Since then, regulators have required more disclosures—calories, trans fats, added sugars—all in the name of public health. But if the goal was to change how Americans eat, the results remain hard to swallow.

Today, nutrition labels are more accurate and comprehensive than ever...