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Protein in Common Foods: Grams per Serving From USDA Data

Protein in everyday foods, from rice and bread to beans, dairy and eggs: grams per serving and per 100 calories, worked out from USDA SR Legacy data.

By Published 4 min read

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AI-assisted article. Drafted with AI tools from the sources cited below and checked by automated tests and an AI editorial review. No person has reviewed it yet. How we write and check articles.

Key takeaways

  • Staple foods add measurable protein: a cup of cooked pasta has about 7 g and a cup of cooked lentils about 18 g, from USDA data.
  • Protein per 100 calories separates protein-dense foods from protein-containing ones: canned tuna has about 22.6 g, white rice about 2.1 g.
  • A day of staples alone, with bread, rice, pasta, vegetables and a cup of milk, can add up to around 35 g of protein.
  • Figures here come from USDA's SR Legacy database and are per stated serving; brands and recipes vary.
  • The FDA's Daily Value for protein on food labels is 50 g, a labelling reference rather than a personal target.

This list starts with staple foods that are not usually thought of as protein sources, such as rice, bread, pasta, potatoes and vegetables, and then covers beans, dairy, eggs, meat and fish. Every figure below is worked out from the US Department of Agriculture's SR Legacy database in FoodData Central, per the serving shown, so you can see what your usual meals already contribute.

How the numbers were worked out

SR Legacy lists nutrients per 100 g of food, along with gram weights for common portions such as "1 cup" or "1 slice". Protein per serving is the per-100 g value multiplied by the portion weight. Protein per 100 calories divides protein by energy, a quick way to tell protein-dense foods from foods that simply contain some. All figures are per the serving shown, not per 100 g, except the per-100 g comparisons in the text. Branded products and home recipes will differ, so treat these as reference values.

Grains and starchy foods

Food Serving Protein Calories Protein per 100 kcal
White rice, long-grain, cooked 1 cup (158 g) 4.3 g 205 2.1 g
Brown rice, long-grain, cooked 1 cup (202 g) 5.5 g 248 2.2 g
Oats, dry ½ cup (40.5 g) 5.3 g 153 3.5 g
Whole-wheat bread 1 slice (32 g) 4.0 g 81 4.9 g
White bread 1 slice (29 g) 2.6 g 77 3.3 g
Pasta, cooked (spaghetti, not packed) 1 cup (124 g) 7.2 g 196 3.7 g
Quinoa, cooked 1 cup (185 g) 8.1 g 222 3.7 g
Potato, baked with skin 1 medium (173 g) 4.3 g 161 2.7 g

Whole-wheat bread has about half as much protein again per slice as white bread. A cup of pasta has about 1.7 times the protein of a cup of white rice: pasta carries more than twice as much protein per gram (5.8 g against 2.7 g per 100 g), even though USDA's cup of pasta weighs less.

Vegetables

Food Serving Protein Calories Protein per 100 kcal
Green peas, cooked from frozen ½ cup (80 g) 4.1 g 62 6.6 g
Sweetcorn, cooked from frozen 1 cup (165 g) 4.2 g 134 3.1 g
Broccoli, raw 1 cup chopped (91 g) 2.6 g 31 8.3 g
Spinach, raw 1 cup (30 g) 0.9 g 7 12.4 g

Spinach shows why both columns matter: it is protein-dense per calorie but so light that a cup gives under a gram.

Beans, soy, nuts and seeds

Food Serving Protein Calories Protein per 100 kcal
Lentils, cooked 1 cup (198 g) 17.9 g 230 7.8 g
Black beans, cooked 1 cup (172 g) 15.2 g 227 6.7 g
Chickpeas, cooked 1 cup (164 g) 14.5 g 269 5.4 g
Tofu, firm, prepared with calcium sulfate and magnesium chloride (nigari) ½ cup (126 g) 11.4 g 98 11.6 g
Peanut butter, smooth 2 tbsp (32 g) 7.1 g 191 3.7 g
Almonds 1 oz (28.35 g) 6.0 g 164 3.7 g

Dairy, eggs, meat and fish

Food Serving Protein Calories Protein per 100 kcal
Milk, 2% 1 cup (244 g) 8.1 g 122 6.6 g
Cheddar, sharp 1 oz slice (28 g) 6.8 g 115 5.9 g
Greek yogurt, plain nonfat 1 container (170 g) 17.3 g 100 17.3 g
Cottage cheese, 2% 1 cup (226 g) 23.6 g 183 12.9 g
Egg, hard-boiled 1 large (50 g) 6.3 g 78 8.1 g
Chicken breast, roasted ½ breast (86 g) 26.7 g 142 18.8 g
Tuna, light, canned in water 3 oz (85 g) 16.5 g 73 22.6 g

A worked example: what staples add up to

Take a day built only from staples: two slices of whole-wheat bread (8.0 g), a cup of brown rice (5.5 g), a cup of pasta (7.2 g), a cup of raw broccoli (2.6 g), half a cup of peas (4.1 g) and a cup of 2% milk (8.1 g). That is about 35 g of protein before any meat, fish, eggs, beans or tofu. For comparison, the FDA's Daily Value for protein, the reference used on food labels, is 50 g a day. It is a labelling reference, not a personal target; how much protein per day explains how reference intakes are set, and a health professional can advise on your own needs.

Using these numbers

Two habits make a reference table useful. First, weigh or measure a serving once, because a "cup" of rice at home may not be USDA's 158 g. Second, log the staples too: as the worked example shows, they add up. Protein sources compared covers protein quality and how to read a high-protein foods list, and high-protein breakfast ideas applies these numbers to one meal.

Protein Diet Tracker, one of our health and nutrition apps, rolls each meal and snack into daily totals for protein, calories, carbohydrates and fat, against goals you set yourself; it does not prescribe a target.

Good to know

Frequently asked questions

How much protein is in a cup of rice?
USDA data give about 4.3 g of protein in a cup (158 g) of cooked long-grain white rice and about 5.5 g in a cup (202 g) of cooked long-grain brown rice.
How much protein is in a slice of bread?
About 4.0 g in a 32 g slice of commercial whole-wheat bread and about 2.6 g in a 29 g slice of commercial white bread, according to USDA SR Legacy data.
Which everyday foods have the most protein per calorie?
In this list, lean animal foods and some dairy lead: canned light tuna in water has about 22.6 g of protein per 100 calories, roasted chicken breast 18.8 g and plain nonfat Greek yogurt 17.3 g. Among plant foods, firm tofu (USDA's entry prepared with calcium sulfate and magnesium chloride) has about 11.6 g and cooked lentils 7.8 g.
Do vegetables have protein?
Some, though servings are small. Raw spinach is high per calorie, about 12.4 g per 100 calories, but a cup weighs only 30 g and gives under 1 g; half a cup of cooked green peas gives about 4.1 g.

Sources

  1. FoodData Central: SR Legacy (April 2018 release) (opens in a new tab)US Department of Agriculture, Agricultural Research Service — accessed
  2. Daily Value on the Nutrition and Supplement Facts Labels (opens in a new tab)US Food and Drug Administration — accessed

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