For most people who aren't that active, the usual equation for how much protein you should eat daily is 0.8 grams of protein per kilogram of bodyweight. So, a 150-pound person would convert their weight to kilograms and multiply that number by 0.8. It would look like this:
0.8 X 68 = 54.4 grams of protein per day.
The more active you are, the more protein you'll need. St. Pierre says that active people should aim for 1.4 to 2.2 grams of protein for every kilogram of bodyweight. You can also use this handy USDA calculator that does all the math for you.
Here are some common foods and how much protein they have per serving:
1 large egg: 6.28 grams
1 slice cheddar cheese: 6.4 grams
1 can of tuna: 40.73 grams
1/4 package of tofu: 7 grams
1/2 cup of black beans: 6 grams
2 slices of roasted turkey breast: 10 grams
2 tablespoons peanut butter: 7.7 grams
1 container plain Greek yogurt: 18 grams
1/2 cup of lentils: 8 grams