Taking in enough fiber is essential for maintaining a healthy body, and is especially important if you’re trying to lose weight. It fills you up and keeps your digestive system running smoothly. What else? Zuckerbrot says, “High-fiber, whole-grain cereal digests slowly, steadying blood sugar levels for sustained energy. It's also loaded with B vitamins, antioxidants, and trace minerals such as iron, zinc, copper, and magnesium."