🥗 Nutrition · 4 min read

Protein: the basics of dietary protein

What protein is

Protein consists of amino acids linked into chains. During digestion these chains are broken back down into their building blocks; from those the body then forms its own proteins. Of the twenty amino acids involved, nine are considered essential, because the body cannot produce them itself.

The turnover is constant: the body’s own protein is continuously broken down and rebuilt. What comes from food enters the same pool. The question of protein intake is therefore not one about building alone, but about the ratio of build-up to breakdown over time.

Where protein occurs

Appreciable amounts are found in meat, fish, eggs and dairy as well as in pulses, soy products, nuts, seeds and, to a lesser extent, grains. Protein content per 100 grams differs considerably — as does how much other energy comes with it.

A frequent misunderstanding concerns dry matter: dried pulses show high figures on the packet, but once cooked they take up water, so the content per portion drops markedly. When comparing figures, it is worth checking whether they refer to the raw or the prepared state.

Protein quality and combination

Not every protein contains all essential amino acids in the same ratio. Scoring systems such as PDCAAS and the newer DIAAS describe these differences by combining amino-acid pattern and digestibility. Animal sources score higher on average than most plant ones.

In practice this is less dramatic than it sounds: across a mixed diet, different sources complement each other in amino-acid pattern. The formerly widespread idea that complementary sources must be combined within the same meal is now considered outdated — the day is what counts, not the plate. With an entirely plant-based diet, composition still needs more deliberate planning.

What amounts are discussed

General population reference values are considerably lower than the ranges named in sports science for people who train. Review papers on resistance training frequently sit in the region of roughly 1.6 to 2.2 grams per kilogram of body weight per day. Where body fat is taken into account, the amount is sometimes based on fat-free mass, which gives more realistic figures at higher body fat levels.

These ranges are broad because the underlying studies are: different training states, different energy intakes, different measurement methods. A single point value within the range cannot responsibly be derived from them. And more is not arbitrarily better — above these regions the data show no clear additional benefit.

Distribution across the day

Whether it matters how the daily amount is distributed across meals is an open question. Some papers suggest an advantage for more even distribution, others find no meaningful difference at equal daily intake. The studies are mostly short and use small groups.

What can defensibly be said: the daily amount is by far the more robust figure. Anyone who reaches it need not optimise distribution; anyone who does not reach it will not compensate through distribution.

What “high protein” on the packaging means

Nutrition claims on foods are regulated across Europe and cannot be chosen freely. Two thresholds apply to protein, both based on the share of energy: a food may be called a “source of protein” if at least twelve percent of its energy value comes from protein, and “high in protein” from twenty percent.

The decisive point is often missed: the yardstick is the share of energy, not the amount per portion. A food low in overall energy reaches the threshold more easily than an energy-dense one — so a product labelled “high in protein” can contain less protein per portion than a food without that label.

Anyone wanting to compare is therefore better served by the nutrition table than the front of the pack: grams of protein per 100 grams or per portion are the figures that can sensibly be set against each other.

Powders and supplements

Protein powder is a food in concentrated, easily stored form — no more and no less. Compared with other protein sources it has no fundamental advantage beyond convenience and the ease of planning an amount.

Anyone meeting their needs through ordinary foods does not require it. This article deliberately gives no specific quantity or intake recommendations: that depends on the rest of the diet, on training volume and on individual circumstances, and with pre-existing conditions — of the kidneys in particular — the question belongs in medical hands anyway.

Last reviewed: 14.08.2026