Why you should eat black bean: Less constipation and bloating: The fiber helps you stay regular. Lower "bad" cholesterol levels: Eating adequate fiber (at least 25 to 35 grams per day) can help decrease LDL cholesterol levels and reduce your risk of heart disease. Protection for your bones: The magnesium in black beans plays a role in over 300 enzymatic reactions in the body including metabolism, and it's key for bone health as well. Healthier blood pressure levels: The potassium in black beans can help improve your numbers.