Most Americans get far more protein than they really need. In theory, that may not be wise. Like carbohydrates, protein provides 4 calories per gram, and excess calories from any source will be stored as body fat. Excess dietary protein increases calcium loss in the urine, perhaps raising the risk for osteoporosis ("thin bones," more a worry for women) and kidney stones (a particular worry for men).
Fiber is an important part of an overall healthy eating plan. Good sources of fiber include fortified cereal, many whole-grain breads, beans, fruits (especially berries), dark green leafy vegetables, all types of squash, and nuts. Look on the Nutrition Facts label for fiber content in processed foods like cereals and breads. Use the search tool on this USDA page to find the amount of fiber in whole foods like fruits and vegetables.