Answered by Norma Lana on Monday, June 1, 2009
Beans are a complete nutrient and fiber package, and low in fat to boot. But according to Janet Helm, R.D., a spokesperson for the American Dietetic Association, technically they are an incomplete protein because they 're lacking one of the nine protein building blocks, or essential amino acids. (Milk, other dairy foods, fish, poultry, meat, and all animal sources of protein contain all of them.) It was once thought that beans must be consumed with foods like rice at every meal to fully replenish your amino acids, says Helm. But "as long as your diet has a mix of amino acids from other protein foods, such as meat, cheese, or hummus during the day, you'll be fine. It's a balance over days and weeks, not hours."