For most Americans, acquiring protein isn't the problem -- 12-18% of their caloric intake consists of protein. The problem is choosing quality sources.
Protein is found in animal products: such as, meat, eggs, and dairy products. Protein can also be found in legumes (beans and peas), tofu, nuts, and seeds as well as whole grains. For comparison, a single cup of milk contains eight grams of protein; three ounces of meat contains 21 grams; one cup of dry beans contains 16 grams; and eight ounces of yogurt contains 11 grams.
Protein is found in animal products: such as, meat, eggs, and dairy products. Protein can also be found in legumes (beans and peas), tofu, nuts, and seeds as well as whole grains. For comparison, a single cup of milk contains eight grams of protein; three ounces of meat contains 21 grams; one cup of dry beans contains 16 grams; and eight ounces of yogurt contains 11 grams.
Consumers adhering to a vegetarian diet should pay special attention to ensure adequate protein consumption, especially if they are avoiding dairy products. At the 2,000 calorie level, 1.5 ounces of nuts and 2/3 cup of legumes (beans or peas) will substitute for 5.5 ounces of animal product. According to the USDA Food Guide, a single egg is equivalent to half an ounce of nuts or one fourth of a cup of legumes. If you'd rather not deal with the numbers yourself, the USDA provides ChooseMyPlate.gov, a website where you can enter in your age, weight and sex in order to see your recommended diet.
While most American do not have to worry about getting to much protein, we should all keep in mind that it may be wise for people with certain medical conditions, such as kidney disease, to limit their intake. Of course, it's best to consult a professional if you aren't sure.
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References
"2005 Dietary Guidelines for Americans." US Department of Health and Human Services and the US Department of Agriculture; 2005.
"Nutrition for Everyone." Centers for Disease Control and Prevention: 2011.
"How Much Protein Do You Need?" NIH News in Health: 2008.
"Dietary Guidelines for Americans 2005." U.S. Department of Health and Human Services: 2005.
"Daily Food Plan. ChooseMyPlate.gov: 2012
"Nutrition for Everyone." Centers for Disease Control and Prevention: 2011.
"How Much Protein Do You Need?" NIH News in Health: 2008.
"Dietary Guidelines for Americans 2005." U.S. Department of Health and Human Services: 2005.
"Daily Food Plan. ChooseMyPlate.gov: 2012