Plant protein sources can meet the daily need, but variety is required for that. According to Türkiye Beslenme Rehberi (TÜBER), Türkiye's national dietary guideline, the essential amino acids are found in animal foods in amounts suited to the requirement, while in some plant sources they are found in limited amounts. The difference is not in the amount of protein but in the amino acid pattern.
Where exactly is the difference?
Dried legumes are matured seeds and their basic composition is carbohydrate and protein. Their protein values are high, but their quality is low. The guideline counts three reasons for this: that they are limited in the essential sulfur-containing amino acids, that their dietary fiber content is high, and that they are hard to digest.
On the animal side the table is reversed. The egg is counted as the reference protein because its proteins are known to be converted into body proteins at a rate of 100 percent. Meat, chicken and fish carry an equivalent amount of protein, and together they are also a source of iron, zinc, phosphorus and vitamin B12. Vitamin B12 is found only in animal foods.
How does pairing close the gap?
The solution the guideline gives is not to add a food but to pair foods. When dried legumes are cooked well and mixed with grains in a certain ratio, the protein quality rises. The concrete example given is a pairing Turkish cuisine already knows: bulgur or rice pilaf beside a dish of dried beans cooked without meat.
The same logic can be read from the grain side too. The protein quality and amount of grains is lower than in the meat and milk groups; when they are consumed together with foods such as dried legumes, milk and eggs, this quality can be raised. So pairing works both ways, and which food you start from makes no difference.
The plant source's own advantages
Dried legumes and oilseeds contain no cholesterol; their total fat and saturated fat content is also fairly low. Their fat content is mostly made up of polyunsaturated fatty acids. Dried legumes are also a source of dietary fiber, oligosaccharides and phytochemicals, and are rich in the minerals calcium, zinc, magnesium and iron.
The iron and the calcium in these sources are in a less usable state in the body. The guideline gives a practical solution for this as well: cooking them well and consuming them together with vegetables and fruits that are a source of vitamin C raises the bioavailability of these minerals.
Which plant foods carry protein?
The main dried legumes are chickpeas, lentils, broad beans, beans, peas, black-eyed peas and soybeans. Alongside these, oilseeds, seeds, grains, vegetables and fruits contribute to the daily total as well. The guideline states that when enough is consumed from these sources through the day, body proteins can be synthesized.
The source pointed to specifically for those who consume no animal product is the soybean; the guideline says soybeans can be consumed in place of meat in order to raise quality protein intake. Dried legumes and oilseeds too, when consumed together as a meat alternative, can meet this group's nutrient need.
How much are the portion equivalents?
The guideline's portion table makes the comparison something you can do by eye. One portion of cooked dried legumes is 130 grams, that is three quarters of a cup or 8-10 tablespoons. One egg is 50 grams, which corresponds to one small egg.
In nuts the measure is smaller: 30 hazelnuts or 4 walnuts come to a handful, that is 30 grams. Of hazelnut or peanut butter, one dessert spoonful is 25 grams. On the milk side a medium cup of milk is 240 milliliters, a cup of yogurt 200 milliliters, one portion of white cheese 60 grams and one portion of kaşar cheese 40 grams.
These measures are read together with the daily portion numbers. The distribution the guideline gives for a vegetarian pattern is 3-6 portions of grains, 3-5 portions of vegetables, 2-4 portions of fruit, 0-3 portions of milk and milk products, and 2-3 portions of eggs and dried legumes a day.
Where does it turn into a mistake?
The first mistake is leaning on a single plant source. The guideline makes variety a condition especially for those who consume no animal product; a pattern built on a single kind of legume runs short on the amino acid side. The second mistake is removing meat and eggs completely and putting nothing in their place.
The third mistake has to do with measure. Nuts and oilseeds are good protein sources but they contain more fat than other foods, so their amounts are watched. The same warning holds for oilseeds; although they are rich in the B group vitamins and in minerals, their portions are kept small. Keeping the handful measure at 30 grams protects this group's protein contribution while also holding the energy side at the limit. You can follow the protein values of foods from the protein tab of the nutrition values table, and the calculation of the daily need from the protein guide.