Researchers of the Harvard Medical School feel that Recommended Dietary Allowance (RDA) for protein is a modest 0.8 grams of protein per kilogram of body weight (The RDA is the amount of a nutrient you need to meet your basic nutritional requirements)
Some of good sources of protein in a day, according to Harvard Medical School, include 3 ounces tuna, salmon, haddock, or trout (21g protein), 3 ounces cooked turkey or chicken (19 g protein), 6 ounces plain Greek yogurt (17 g protein)
Meanwhile, other good sources of protein to have in a day include ½ cup cottage cheese (14 g protein), ½ cup cooked beans (8g protein), 1 cup of milk (8g protein), 1 cup cooked pasta (8g protein), ¼ cup or 1 ounce of nuts (all types) ( 7 g protein) and 1 egg (6g protein)