The proteins in our bodies are constantly being broken down into amino acids. Amino acids combine to form proteins in your body. Some amino acids can be synthesized in your body, but essential amino acids cannot. There are nine amino acids that we can only receive through the food we eat. We can replace the essential amino acids by eating a variety of foods from the protein food group. Foods from this group contain proteins as well as other nutrients like B vitamins, vitamin E, iron, zinc, and magnesium. Animal sources of protein include meat, poultry, seafood, milk and milk products, and eggs. Plant sources of protein include soy products, beans and peas, and nuts and seeds.
Tip: Eating lean proteins from whole food sources is the best way to meet your protein needs!
Protein is also found in grains and vegetables, but in lower amounts. Grains and vegetables do not supply all the essential amino acids, with the exception of quinoa. Quinoa is a grain that has 4 grams of protein in ½ cup and supplies all the essential amino acids. Most Americans eat enough food from the protein group. The table at the bottom of the page indicates the daily recommended dietary allowances for different age groups.
|Age||RDA grams/day||RDA oz/day|
|Children||1-3 years old||13||2|
|4-8 years old||19||3|
|Girls||9-13 years old||34||5|
|14-18 years old||46||6|
|Boys||9-13 years old||34||5|
|14-18 years old||52||7 1/2|
|Women||19-51+ years old||46||6|
|Men||19-51+ years old||56||8|
Examine Your Choices
|Food||Source||What I buy||What I plan to buy/change|
|Protein||Protein powder||Whey protein powder||Low-fat or 2% milk|
|Protein||Meat||83% ground beef||90% extra-lean ground beef or 90% ground turkey|
Here are some examples of the amounts of protein in foods:
- 1 cup of milk has 8 grams of protein.
- A 3-ounce piece of meat has about 21 grams of protein.
- An 8-ounce container of low-fat plain yogurt has about 12 grams of protein.
- An ounce of almonds (about 23 whole almonds) has about 6 grams of protein.
- 1 cup of canned black beans has about 15 grams of protein.
- 1 egg has 6 grams of protein.
These five items add up to 62 grams of protein, more than enough to satisfy the needs of an adult man or woman.
What If I'm a Vegetarian or Vegan?
Vegetarians and vegans avoid eating protein from animal sources. Their protein needs can be met by eating a variety of plant-based foods such as beans, nuts, nut butters, peas, and soy products like tofu and tempeh. Lacto-ovo vegetarians may also choose to eat milk, dairy products, and eggs.
What about Athletes?
Protein plays an important role in repairing and strengthening muscle tissue, which is why this food group is especially important in an athlete's diet. For this reason, high-protein diets are becoming very popular among athletes. But how much is really necessary? 1.2 to 1.7 grams of protein per kilogram of body weight per day is recommended for power athletes while 1.2 to 1.4 grams per kilogram of body weight per day is recommended for endurance athletes. That's about 84 to 119 grams a day for adult male athletes and 66 to 94 grams a day for adult female athletes.
Protein supplements, specifically protein powder, have become a hot item on the market that claim to have better quality than protein found in food. These are believed to lead to an increase in muscle mass and reduced recovery time after workouts. The protein powders are great for convenience, but they are not necessary, even for the most elite athletes. Most athletes and non-athletes can get the recommended amount of protein through diet alone, without the use of supplements. Also, protein supplements lack important nutrients that whole food protein sources contain. If a very busy athlete is searching for a convenient way to meet their protein needs, then a protein shake may be recommended. Other than that, it's best to meet protein needs by eating whole food sources like lean meats, poultry, dairy, beans, nuts, seeds, and fish. A glass of milk contains 8 grams of protein and is just as convenient as a protein powder. If you're looking for a protein boost in your protein shake, try adding ground nuts or low-fat yogurt instead of protein powders.
Choose lean proteins. Some lean beef cuts include round steaks and roasts, top loin, and top sirloin. Lean pork choices include pork loin, tenderloin, center loin, and ham. As for ground products like ground beef or ground turkey, look for labels that say at least "90% lean." Boneless, skinless chicken breasts and turkey cutlets are the leanest poultry choices. Bologna and salami are deli meats that are higher in fat. Instead, choose lean turkey, ham, or low-fat luncheon meats.
Strawberry Fruit Smoothie
Serving size: 1 cup
Yield: 2 servings
- 6 to 8 ice cubes
- 1 cup skim milk
- 8 ounces low-fat vanilla yogurt
- 10 strawberries
Combine all ingredients in a blender. Blend and serve at once.
180 kcal, 29 g carbohydrate, 11 g protein, 2 g fat, 150 mg sodium, 10 mg cholesterol, 2 g fiber.
For this recipe and more yogurt recipes, visit the National Dairy Council
American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada (2009). "Nutrition and Athletic Performance." Medicine and Science in Sports and Exercise 41: 709-731. DOI: 10.1249/MSS.0b0 13e318190eb86.
Caspero, A. (2013). "Protein and the Athlete: How much Do You Need?" In Academy of Nutrition and Dietetics: It's all About Eating Right. Centers for Disease Control and Prevention (2012). "Nutrition for Everyone: Protein."
Institute of Medicine Food and Nutrition Board. "Dietary Reference Intakes (DRIs): Estimated Average Requirements." Retrieved December 2014.
USDA ChooseMyPlate.gov. "Protein Foods." Retrieved December 2014.
Prepared by Lindsay Besecker, nutrition intern, and Lynn James, M.S., R.D.N., L.D.N., senior extension educator. Reviewed by Nancy Routch, R.D.N., nutrition, diet, and health extension educator.