In the search for good sources of lean protein, don't overlook kidney beans. They're an excellent source of protein, and they're naturally low in fat. The U.S. Department of Agriculture's ChooseMyPlate website notes that beans possess a nutritional profile that places them in both the protein group and the vegetable group. In addition to protein, kidney beans are a good source of fiber, vitamins and minerals.
Protein in Kidney Beans
One cup of cooked kidney beans contains 15 grams of protein. To highlight what a significant source of protein they represent, consider that the top sources of protein -- lean meat and poultry -- have about 25 grams in a 3-ounce serving, while fish has 20 grams per serving, according to the USDA. After beans, the next best sources of protein -- milk and yogurt -- only provide 8 grams in a 1-cup serving.
Healthy women should consume 46 grams of protein daily, while men need to eat 56 grams, according to the Institute of Medicine. Your protein needs can change, depending on your general health and activity level. If you're active, you may need extra protein because exercise breaks down muscle protein, according to Iowa State University. If you participate in light to moderate endurance activities, the Academy of Nutrition and Dietetics suggests consuming 0.55 to 0.8 grams of protein per pound of body weight daily. The demands of heavy endurance training may require 0.7 to 0.9 grams of protein per pound.
Boost the Bean's Protein
Your diet must include nine amino acids because they're the ones your body can't produce on its own. Foods with a specific amount of all nine amino acids are called complete, or quality, proteins. Kidney beans contain all nine, but they're a little short on methionine, so they're not a complete protein. The interesting thing about beans is that they're a good source of lysine, which is the amino acid other plant-based foods, such as grains, usually lack, according to VeganHealth.org. When you combine kidney beans with a grain such as rice, you end up with a dish that supplies quality protein.
Health Benefits Beyond Protein
Kidney beans are a great way to add fiber to your diet. One cup has 11 grams of fiber, which is nearly half of the recommended daily intake for women and one-third of the amount men should consume in a day. Fiber fills you up, balances blood sugar, keeps you regular, and prevents cardiovascular disease by lowering cholesterol. One cup of beans has 225 nutrient-dense calories and barely 1 gram of fat. They're a good source of iron, potassium, zinc, and vitamins K and B-6. You'll also get half of your recommended dietary allowance for folate from eating 1 cup of kidney beans.
- USDA Nutrient Database: Beans, Kidney, All Types, Mature Seeds, Cooked, Boiled, Without Salt
- USDA National Agricultural Library: Protein and Amino Acids
- ChooseMyPlate.gov: Beans and Peas Are Unique Foods
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- Iowa State University: Protein
- Academy of Nutrition and Dietetics: Eat Right for Endurance
- VeganHealth.org: Protein
- Oklahoma State University: Dietary Fiber