Kidney beans cooked by boiling are 67% water, 23% carbohydrates, 9% protein, and contain negligible fat (table). In a 100 gram reference amount, cooked kidney beans provide 530 kJ (127 kcal), and are a rich source (20% or more of the Daily Value, DV) of protein, folate (33% DV), iron (22% DV), and srus (20% DV), with moderate amounts (10â19% DV) of thiamin, copper, magnesium, and zinc (11â14% DV)