Dry cereal can be a good option for breakfast, at home or on the go. If you make healthy choices, that is. Three key features to consider are fiber, calories and sugar. Choose cereal that has at least 3 grams of fiber a serving, but aim for 5 or more. Aim for cereal with less than 120 calories a serving if you're dieting. And because many cereals, even those for adults, can be high in added sugar, look for those with less than 13 grams a serving.