Black eyed peas are rich in various types of nutrients. It is an excellent source of fiber, protein, iron, potassium. It is very low in fat and calories. One cup of cowpea contains 11.1 grams of fiber, 13.22 grams of protein, 4.29 milligrams of iron, 475 milligrams of potassium, 0.91 grams of fat and 198 calories.