Among legumes, black beans hold the prize as richest source of soluble fiber; each cup provides nearly five grams of this potent cholesterol-lowering agent. In fact, beans may hold the record for most soluble fiber among the whole plant kingdom; a 1/2 cup of cooked black beans carries nearly twice the soluble fiber of oats. Early studies in animals suggest that most of this soluble fiber is concentrated in the inner part of the bean (not the skin).
How much is good? Start with 1/2 cup per day and work up to a cup of black beans or any kind of bean to make the biggest impact on cholesterol.