Macronutrient
Protein
The RDA is the amount that prevents deficiency in almost everyone — which is a different question from the amount that is optimal for an athlete, or for someone over seventy trying not to lose muscle.
What it does
Protein is not primarily fuel. It is material: enzymes, antibodies, transport proteins, collagen, the contractile machinery of muscle, and every hormone that is not a steroid. The body has no protein store the way it has a fat store — everything that is protein is already doing a job, so a shortfall means dismantling something that was in use.
Nine of the twenty amino acids cannot be made and must arrive in food. What "complete" means is that a protein contains all nine in useful proportion; animal proteins generally do, and most single plant proteins are low in one or two.
That is less of a problem than it was once thought. Eating a variety of plant proteins across a day covers the pattern comfortably — the idea that they had to be combined at the same meal was withdrawn decades ago.
How much you need
| Who | Per day | Note |
|---|---|---|
| Infants, 0–6 months | 9.1 g | Adequate Intake |
| Infants, 7–12 months | 11 g | — |
| Children, 1–3 years | 13 g | — |
| Children, 4–8 years | 19 g | — |
| Children, 9–13 years | 34 g | — |
| Men, 19 and over | 56 g | At a reference body weight |
| Women, 19 and over | 46 g | At a reference body weight |
| Adults, per kilogram | 0.8 g/kg | The figure the others are derived from |
| Pregnancy and breastfeeding | 71 g | — |
The per-kilogram figure is the real recommendation; the gram totals are it applied to an average body. And it is explicitly a minimum. Research in older adults and in people training seriously points to higher intakes — often 1.0–1.6 g/kg — being better for holding on to muscle. That is a different question from the one the RDA answers, and it is worth not confusing the two.
From our own data
The foods highest in protein
Ranked by grams per 100 g. Read it knowing that concentration is not the whole story: a food can be 25% protein and still contribute less to a day than something less dense that you eat more of.
- 1
Soy flour, low-fat100% · DV - 2
Parmesan, low salt83% · DV - 3
Bacon, cooked78% · DV - 4
Soybeans, roasted and salted77% · DV - 5
Veal topside, lean, braised73% · DV - 6
Lupin beans, dry72% · DV - 7
Lamb shoulder, lean, braised71% · DV - 8
Beef brisket, lean, braised69% · DV - 9
Chicken breast, skinless, fried67% · DV - 10
Mutton, roasted67% · DV - 11
Cuttlefish, cooked65% · DV - 12
Pheasant, cooked65% · DV
Per 100 g, from our copy of USDA FoodData Central, against a Daily Value of 50g. Ranked by amount, not by how much of it your body actually takes up — read the next section before you act on the order.
The table above is per 100 g. The app weighs the portion you actually ate.
What helps, and what gets in the way
Helps
- Spreading it across meals rather than loading dinner — muscle protein synthesis responds per meal
- Variety among plant sources, which covers the amino acid pattern without any planning
- Resistance exercise, without which extra protein is largely just calories
Gets in the way
- Very low overall energy intake, where protein gets burned for fuel instead of used
- Advanced age, which blunts the muscle response to a given dose
- Some kidney conditions, where intake needs a clinician’s input rather than an article’s
Protein quality can be measured, and the current standard is DIAAS, which scores how digestible each essential amino acid actually is. Dairy and egg score highest; most single plant sources lower, chiefly through fibre and antinutrients slowing digestion. It matters most at low total intakes and hardly at all at generous ones.
Who tends to fall short
Groups where intake or absorption is commonly lower than the reference. It is a list of populations, not a list of symptoms — it cannot tell you anything about yourself.
- Older adults, whose intake often falls just as their requirement rises
- People recovering from illness, surgery or injury
- People eating very restricted diets for weight loss
- Some vegans with low total energy intake, though a varied plant diet covers it easily
Cook it
Greek yoghurt bowl with seeds and lentil crumble
One, ten minutes
Ingredients
- 200 g Greek yoghurt, full fat
- 3 tbsp cooked green lentils
- 1 tbsp pumpkin seeds
- 1 tbsp hemp seeds
- 1 tsp olive oil
- Lemon zest
- Black pepper and flaky salt
Method
- 1Use strained yoghurtGreek or skyr, not ordinary yoghurt. Straining removes whey and roughly doubles the protein per spoon, which is the entire reason this works.
- 2Crisp the lentilsCooked lentils, patted dry, into a hot pan with the oil for four minutes until some of them pop and go crunchy. Wet lentils will not crisp.
- 3Toast the seeds with themIn for the last ninety seconds, so they warm through without burning.
- 4Assemble savouryYoghurt in the bowl, lentils and seeds over, lemon zest, salt and a lot of pepper. This is a savoury breakfast and it is better for it.
About thirty grams of protein from three ingredients, and it takes ten minutes — which matters more than the number, because a protein target is met by what you will actually make on a Tuesday.
Sources
- Dietary Reference Intakes for Energy, Carbohydrate, Fibre, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids
- WHO/FAO/UNU — Protein and Amino Acid Requirements in Human Nutrition
- USDA FoodData Central
This page is education, not medical advice. It does not diagnose anything and it is not a substitute for a clinician who knows your history. If you think you are short of protein, the answer is a blood test and a conversation, not a supplement bought on the strength of an article.
Every food above, and 12,601 more, with the full panel — in the app.