Protein
Protein supplies amino acids, the parts the body uses to build muscle, enzymes, hormones and antibodies. The US RDA for adults is 0.8 g per kg of body weight a day; active adults need more.
0.8 g per kg of body weight a day
50 g on EU food labels (reference intake), the figure behind label percentages
Your own number · Work it out with the macro calculator
- Most per 100 g 38.5g Soy nuts
- Most per portion 36g 1 small chicken breast
- Energy 4kcal/g same as carbohydrate
- Essential amino acids 9 must come from food
Daily amount: the US RDA for adults aged 19 and over, set per kg of body weight (National Academies). Food figures per 100 g from USDA FoodData Central; per portion, only for foods with a Caltide calorie page.
Foods High in Protein
Ranked per 100 g, with what a usual portion gives, limited to 3 foods per category. Foods with a Caltide calorie page link to it.
S
Soy nuts
37 g in 1 cup
38.5g / 100 g
B
Bacon
Nutrition facts
37.4g / 100 g
P
Parmesan
30.5g / 100 g
V
Venison steak
25 g in 1 patty
30g / 100 g
P
Pumpkin seeds
43 g in 1 cup
29.8g / 100 g
G
Gruyère
29.8g / 100 g
C
Chicken breast
36 g in 1 small breast
Nutrition facts
29.6g / 100 g
V
Veal chop
27 g in 1 chop
29.5g / 100 g
M
Marinated chicken breast
17 g in 1 medium slice
29.1g / 100 g
B
Beef roast
17 g in 1 regular/thin slice
29.1g / 100 g
T
Turkey
8.6 g in 1 small or thin slice
Nutrition facts
28.8g / 100 g
B
Beef mince
24 g in 1 patty
Nutrition facts
27.7g / 100 g
Per 100 g vs. a Usual Portion
Why the food that ranks first per 100 g can give less in a real serving.
| Food | Usual portion | Per 100 g | Per portion |
|---|---|---|---|
| Chicken breast | 1 small breast (120 g) | 29.6g | 36g |
| Lentils | 1 cup (180 g) | 9g | 16g |
| Greek yogurt | 1 pot (150 g) | 8.8g | 13g |
| Egg | 2 eggs (100 g) | 13.5g | 14g |
| Peanut butter | 2 tablespoons (32 g) | 22.2g | 7.1g |
| Almonds | 1 handful (28 g) | 21g | 5.9g |
Two eggs and a cup of cooked lentils land close together per portion, though lentils have a third less protein per 100 g, because a cup of lentils weighs nearly twice as much.
What Is Protein?
Protein is a chain of amino acids. Digestion breaks the chains apart, and the body links the amino acids back together in new orders to make the proteins it needs: muscle fibers, the collagen in skin and bone, enzymes that run digestion and energy use, hemoglobin that carries oxygen, and antibodies.
About 20 amino acids make up the proteins in the body. Nine of them are essential, meaning the body cannot make them and food has to supply them; leucine and lysine are two. The rest the body can build from other amino acids.
Why the Body Needs Protein Every Day
The body has no protein store the way it stores fat or glycogen. Proteins are broken down and rebuilt all the time, and some of the amino acids are lost along the way, so a fresh supply is needed each day. Amino acids eaten beyond what the body can use are burned for energy or turned into glucose or fat.
Why 100 g of Food Is Not 100 g of Protein
Grilled skinless chicken breast is about 30% protein by weight; most of the rest is water. So 100 g of chicken breast gives 29.6 g of protein, and reaching 50 g from chicken alone takes about 170 g of it. Beans and lentils are lower again, about 9 g per 100 g cooked, because they absorb water as they cook.
Which Foods Give the Most Protein per Calorie
Ranking per 100 g makes nuts and nut butters look like protein foods. Per calorie, they are mainly fat. If you want more protein without many more calories, protein per 100 kcal is the fairer comparison.
| Food | Protein per 100 g | kcal per 100 g | Protein per 100 kcal |
|---|---|---|---|
| Cod, baked | 22.3g | 95kcal | 23.6g |
| Chicken breast, grilled | 29.6g | 176kcal | 16.8g |
| Egg, boiled | 13.5g | 134kcal | 10.1g |
| Greek yogurt | 8.8g | 94kcal | 9.3g |
| Lentils, cooked | 9.0g | 115kcal | 7.8g |
| Peanut butter | 22.2g | 598kcal | 3.7g |
Peanut butter and cod have almost the same protein per 100 g, yet for the same calories cod gives more than six times as much.
How Much Protein a Day of Ordinary Meals Gives
A day of ordinary meals from our library, in usual portions, with no protein powder:
| Meal | Food | Amount | Protein |
|---|---|---|---|
| Breakfast | Oats | 40g | 5.3g |
| Breakfast | Greek yogurt | 150g | 13g |
| Lunch | Bread | 50g | 4.7g |
| Lunch | Tuna | 107g | 20g |
| Snack | Almonds | 28g | 5.9g |
| Dinner | Chicken breast | 120g | 36g |
| Dinner | Rice | 160g | 4.3g |
| Dinner | Broccoli | 90g | 2.3g |
| Total | 92g |
Most adults who eat meat or fish at two meals pass the US RDA, about 46 g for an average woman and 56 g for an average man. The people more likely to fall short are older adults with small appetites and people eating very little overall.
Can Plant Foods Cover Your Protein Needs?
Meat, fish, eggs, dairy and soy contain all nine essential amino acids in useful amounts. Most other plant foods are low in one: grains in lysine, beans and lentils in methionine. Eating both across the day covers the gap, so a vegetarian diet with beans, grains, nuts and dairy or soy can meet protein needs.
Common Protein Mistakes
Counting the weight of the food. A 150 g steak is not 150 g of protein; it is about 40 g.
Calling nuts a protein food. A handful of almonds gives about 6 g of protein and about 15 g of fat.
Treating all powders as the same. Collagen powder counts as protein on a label but lacks tryptophan, so it cannot replace a complete protein.
How Much Protein Do You Need?
Protein is set per kg of body weight, and the right amount depends on your goal.
| Goal | Grams a day |
|---|---|
| Most adults (US RDA) 0.8 g per kg |
60 kg 48g 75 kg 60g 90 kg 72g |
| Adults in Europe (EFSA) 0.83 g per kg |
60 kg 50g 75 kg 62g 90 kg 75g |
| Active adults (ACSM, ISSN) 1.2-2.0 g per kg |
60 kg 72-120g 75 kg 90-150g 90 kg 108-180g |
| Keeping muscle while dieting, or building it (ISSN; Morton et al. 2018) 1.6-2.2 g per kg |
60 kg 96-132g 75 kg 120-165g 90 kg 144-198g |
For a number based on your own weight, goal and calorie target, use the macro calculator.
| Age | Male | Female |
|---|---|---|
| 1 - 3 years | 13g | 13g |
| 4 - 8 years | 19g | 19g |
| 9 - 13 years | 34g | 34g |
| 14 - 18 years | 52g | 46g |
| 19+ years | 56g | 46g |
| Pregnancy | - | 71g |
Protein Powders and Supplements
Powders are food protein, dried and concentrated. They count toward the day like any other source.
| Powder | Made from | What to know |
|---|---|---|
| Whey | Milk | Complete protein, digested quickly; whey concentrate contains some lactose, isolate much less |
| Casein | Milk | Complete protein, digested more slowly than whey |
| Soy | Soybeans | Complete plant protein; suits vegans |
| Pea | Yellow peas | Plant protein, lower in methionine; often blended with rice protein |
| Collagen | Animal skin and bone | Lacks tryptophan, so it is not a complete protein |
How to Read a Protein Powder Label
Look at grams of protein per scoop, not the scoop weight. A 30 g scoop is never 30 g of protein: flavoring, sweetener and carbohydrate make up part of it, and the share differs a lot between products.
Why Protein Foods Beat Powders
Protein foods bring iron, zinc, vitamin B12, calcium or fiber with them; a shake brings only what the label lists. Powders are dietary supplements, which are not approved for safety or content before they are sold in the US.
Tracking Protein in Caltide
- A goal of your ownCaltide sets your protein goal from your body weight and calorie target, and you can change it in Settings.
- Logged automaticallyEvery food you log, and every protein powder you add as a food or tick off as a supplement, counts toward the day's protein.
Protein Sources and References
The figures and claims on this page are checked against these sources. Food amounts come from USDA FoodData Central.
- National Academies: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005)
- EFSA: Scientific Opinion on Dietary Reference Values for protein (2012)
- International Society of Sports Nutrition Position Stand: protein and exercise (2017)
- Morton et al. (2018): Protein supplementation and resistance training-induced gains in muscle mass and strength, a systematic review and meta-analysis
- USDA FoodData Central
Questions About Protein
The US RDA for adults is 0.8 g per kg of body weight a day, 60 g for a 75 kg adult; EFSA sets 0.83 g per kg. Active adults are advised 1.2 to 2.0 g per kg (ACSM, ISSN), and 1.6 to 2.2 g per kg helps keep muscle while dieting or build it (ISSN; Morton et al. 2018). For your own number, use the macro calculator.
In our food library, soy nuts: 38.5 g per 100 g. Bacon (37.4 g) and Parmesan (30.5 g) come next. Meat, hard cheese, soy nuts and seeds lead per 100 g.
A boiled egg has 13.5 g of protein per 100 g, so one 50 g egg gives just under 7 g.
No. Grilled skinless chicken breast is about 29.6% protein by weight; the rest is mostly water. Food weight and protein weight are different numbers.
No upper limit has been set for healthy adults. EFSA considers up to twice its reference, about 1.7 g per kg a day, safe, and sports nutrition groups advise up to 2.2 g per kg for training. People with kidney disease are often told to limit protein, so they should follow their doctor's advice.
Usually, yes, if they eat a variety of beans, lentils, soy, grains, nuts and dairy or eggs. The amino acids from different plant foods eaten across the day complement each other; they do not need to be combined in one meal.
Not if food already covers your needs. A powder is a convenient source, not a better one. Whey, casein, soy and pea powders are complete proteins; collagen powder lacks the essential amino acid tryptophan.
About 4 kcal, the same as carbohydrate and less than half of fat at 9 kcal.
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