Prunes, which are dried plums, also have loads of fiber -- something your grandpa might have mentioned. They go great with nuts, cheese, or yogurt. They do have lots of sugar though -- about 30 grams per ½ cup. Makers often add extra sugar to dried fruits, so keep an eye on that if you want to limit calories. If you’d rather drink your prunes, try just 6 ounces of juice, which has almost as much potassium.