High-protein foods: comparative analysis and recommendations for a healthy diet

Proteins are vital nutritional elements that act as “building blocks” for cells, muscle tissues, enzymes and hormones.

Adequate protein intake is essential for maintaining muscle mass and normal body function.

Studies show that protein-rich meals satisfy hunger better and prolong satiety, helping to control appetite.

In today’s world, where more and more people are striving for a healthy lifestyle, the topic of protein products is of particular importance.

Below we will look at the differences between plant and animal proteins, how they are digested, their impact on health (benefits and possible risks) and what are scientifically based recommendations for protein consumption.

Plant and animal proteins: a comparison

Amino acid profile and completeness

Proteins are made up of amino acids – some of which the body cannot synthesize on its own (essential amino acids) and must be obtained from food.

Animal products (meat, fish, eggs, milk) contain a full set of essential amino acids in sufficient quantities, so such proteins are called “complete”.

Plant sources (legumes, grains, nuts) often have an incomplete amino acid profile – each may lack one or more essential amino acids.

However, this does not mean that plant protein is inferior: with a varied diet, a combination of different plant foods ensures that all essential amino acids are supplied.

For example, cereals are rich in methionine but poor in lysine, while legumes are the opposite; eating them together (e.g. rice and beans) can provide a balanced amino acid composition.

Absorption and bioavailability

Animal proteins are generally more easily and completely digested by the body. They have high digestibility and provide a higher concentration of amino acids in the blood after a meal.

Plant proteins, on the other hand, may be less digestible due to the presence of dietary fiber and anti-nutrients (such as phytates) in plant foods. This means that amino acids from plant foods are not always fully available to the body.

However, modern technology and culinary processing can increase the digestibility of plant protein.

For example, fermenting soybeans at tempeh or using protein blends from different plants improves digestion – studies show that isolated plant proteins or blends of them can stimulate muscle protein synthesis almost as effectively as animal proteins.

Thus, with a properly formulated diet, vegetable protein can fully cover the body’s needs.

Additional nutrients

In addition to protein, animal products are a source of important substances: iron (in the easily digestible heme form), vitamin B₁₂, calcium (dairy products) and zinc. At the same time, they may contain more saturated fat and cholesterol.

Plant foods are rich in fiber, antioxidants, a number of vitamins (such as folic acid) and contain no cholesterol. Nuts and seeds, which are rich in protein, also provide healthy unsaturated fats.

In general, experts recommend combining different sources of protein in the diet – this allows you to get the maximum benefit: and complete amino acids from animal products, and fiber with phytonutrients from plant products.

The effect of proteins on the body: benefits and possible risks

Benefits of adequate protein intake

Sufficient protein in the diet is associated with a number of positive effects.

First, protein is essential for maintaining and building muscle mass. In older adults, increased protein intake (above the minimum intake) helps prevent sarcopenia, an age-related decline in muscle mass and strength.

Second, protein foods help control weight.

Protein-rich diets are often more effective for weight loss because protein increases satiety and thermogenesis (energy expenditure to digest food).

Clinical studies show that a high-protein diet promotes greater fat loss while preserving muscle and reduces the risk of weight regain.

Moreover, in studies of 6-12 months duration in healthy individuals, no adverse effects of increased protein intake on bone density or kidney function were observed.

Protein is also essential for tissue healing, recovery from injury and disease, and immune support.

Risks of redundancy and source quality

Despite the benefits, a very high protein intake or the predominance of certain protein sources can have undesirable effects.

The main possible risks are not so much related to the protein itself, but rather to the accompanying substances in the products.

For example, fatty red meat and processed meat products (sausages, bacon) are rich in protein but high in saturated fat and salt.

Their excessive consumption is associated with an increased risk of cardiovascular disease and certain types of cancer (e.g., colorectal) according to epidemiologic studies.

Therefore, nutritionists recommend limiting the consumption of processed meat and favoring lean meats.

Another issue is the effect of excess protein on the kidneys. A moderate increase in protein in the diet is not harmful to healthy people, but in those who already have kidney disease, excess protein can increase the burden on the kidneys.

High protein intake leads to increased filtration of blood in the kidneys (hyperfiltration). Over time, this can potentially contribute to wear and tear on the tubules and the development of proteinuria – the appearance of protein in the urine.

There is evidence from observational studies that very high animal protein intake is associated with an increased risk of chronic kidney disease compared to plant-based protein.

However, for healthy individuals, the upper tolerances for protein intake are sufficiently high and, in the absence of a predisposition to nephropathy, a protein diet within reasonable limits does not cause renal impairment.

It is important to keep a balance and not to exceed recommended limits unnecessarily (for example, bodybuilders sometimes consume excessive amounts of protein, which provides no additional benefit and only stresses the organs).

Interesting data has been obtained regarding the relationship of protein intake to overall life expectancy. A large meta-analysis from 2020 (32 prospective studies involving >700,000 people) showed that higher total protein intake was associated with a lower risk of all-cause mortality.

Plant protein was particularly favorable – people who received more protein from plant sources had a statistically significant reduction in cardiovascular disease mortality.

The authors conclude that replacing part of animal protein in the diet with vegetable protein may be useful for prolonging human life.

This is consistent with modern ideas about the benefits of the Mediterranean and other plant-based diets, where protein comes not only from meat, but also from fish, legumes, and nuts. Thus, not only the quantity but also the quality of protein foods is important for health.

Recommendations for protein intake

Daily allowance and individual needs

Protein requirement depends on age, level of physical activity and physiological state of a person. The generally accepted norm for an adult is 0.8 g of protein per 1 kg of body weight per day.

This corresponds to about 55-60 g of protein per day for a person weighing ~70 kg. This value covers the minimum requirements of most healthy people and prevents deficiencies. However, for optimal health, it is advisable for many populations to consume slightly more protein:

• Elderly people. Protein absorption deteriorates with age and the need for protein increases to prevent sarcopenia. The International Guideline recommends that people over 65 years of age consume an average of 1.0-1.2 g/kg per day.That is, a 70-year-old person weighing 70 kg should preferably get about 70-84 g of protein per day. This helps to preserve muscle strength, improves recovery after illness and injury in the elderly.
• Athletes and active people. During intense physical activity, the need for protein is higher, as it is spent on the recovery and growth of muscle tissues. Sports nutritionists recommend ≈1.2-2.0 g/kg for adults who exercise regularly (the exact figure depends on the type of exercise, the goal – mass gain or endurance – and individual characteristics)For example, an 80 kg athlete may require 96-160 g of protein per day. This range covers the needs of both strength athletes and endurance runners. Evenness is important: for optimal muscle protein synthesis, it is best to divide daily protein into 3-4 meals, each containing ~20-40 g of protein.
• Pregnant and lactating women. During pregnancy, the need for protein increases to support fetal growth. The recommended amount in the 2-3 trimester is about 1.1 g/kg body weight per day (about 20-25 g more than before pregnancy).(about 20-25 g more than before pregnancy). Breastfeeding mothers also need additional protein (about +20 g per day) to synthesize breast milk.

• Children and adolescents. During the growth period, more protein per kg of weight is required. For example, ~1.2 g/kg is recommended for preschoolers, ~1.0 g/kg for children 7-10 years of age, and ~0.9 g/kg for adolescents. It is important for normal development of a child to get enough protein from a variety of foods, but in developed countries, children usually get the necessary protein from their daily diet automatically.

It is important to emphasize that an excessive protein intake (more than 2.5-3 g/kg) is usually unjustified, unless it is a specially designed sports diet. Excess protein is not stored “in reserve”: it is either used as a source of energy or is eliminated from the body, creating unnecessary stress. This is why you should stick to the recommended ranges and not try to exceed the norm.

Food selection and balanced diet

It is recommended to favor varied and predominantly lean sources to meet protein requirements:

• Include lean meats (skinless poultry, lean beef, veal, rabbit) and fish. These foods are rich in complete protein and at the same time contain iron, zinc, vitamin B₁₂. Fish (especially sea fish – salmon, herring, mackerel) additionally provides the body with omega-3 fatty acids.

• Don’t forget about dairy products. Skim or low-fat cottage cheese, Greek yogurt and cheeses contain a lot of protein and calcium. For example, 100 g of cottage cheese is ~12-15 g of protein with relatively low calories. Choose fermented dairy products without added sugar.

• Eggs are an excellent source of digestible protein, vitamins and choline. One medium egg contains ~6-7 g of protein. Adults without elevated blood cholesterol can eat 1-2 eggs per day as part of a healthy diet.

• Legumes and cereals. Among plants, legumes are the record holders in protein content: lentils, chickpeas, soybeans, beans. In 100 g of dry lentils ~24 g of protein, in chickpeas – about 20 g. Although in the cooked (boiled) form due to water the protein content will be ~8-9 g per 100 g, legumes are still a valuable protein side dish. Whole-grain cereals (oats, quinoa, buckwheat) also contribute to the protein balance – 100 g of dry cereal usually contains 10-13 g of protein.

• Nuts and seeds – almonds, peanuts, walnuts, pumpkin and sunflower seeds. They contain 20-30 g of vegetable protein per 100 g, but they are also high in calories due to fat. A small handful (20-30 g) a day is enough as a snack or addition to meals.

For clarity, below is a table with the protein content of various foods:

Table 1. Protein content in products (g per 100 g)

Note: Protein content values are rounded and averaged.

For foods that are consumed cooked (meat, fish, legumes, etc.), the data are for the raw product.

Characteristic conditions (e.g. dry weight for cereals and legumes, or method of preservation) are given in brackets. As can be seen, lean meats, hard cheeses, and some concentrated plant foods like nuts and legumes are the most protein-rich.

However, in addition to the amount of protein, it is important to consider the nutritional value of foods – their calorie and fat/carbohydrate content. The table below illustrates that a “protein” product can be both dietary and very caloric, depending on the accompanying nutrients:

Table 2. Caloric content and composition of some protein products (per 100 g)

Note: Data are averaged. The fat content of meat and fish may vary depending on the part of the carcass and cooking method, which affects the calorie content.

Analyzing the table, you can notice significant differences: for example, 100 g of chicken breast or fish provide ~20-30 g of protein with relatively few calories, while 100 g of cheese or nuts contain a comparable amount of protein, but calories are several times higher due to the high fat content.

Therefore, if the goal is to control weight, it is preferable to choose leaner sources of protein (poultry, fish, low-fat cottage cheese) and moderately include high-calorie protein products (cheese, nuts) in small amounts in the diet.

On the other hand, nuts and vegetable oils are an important part of a balanced diet, it’s just that their portions should be limited (e.g. ~30g of nuts per day).

Practical tips:

• Try to include protein at every meal. For example, eggs or cottage cheese for breakfast, a portion of meat/fish or legumes for lunch, cottage cheese or fish for dinner, and supplement your snacks with yogurt or a handful of nuts. This way the body will be evenly supplied with amino acids throughout the day.

• Favor less fatty cooking methods: boiling, baking, grilling without excessive oil. In this way, you will retain the high protein content, but reduce the calorie content of the dish at the expense of excess fat.

• Combine vegetable and animal proteins. For example, prepare meat dishes with vegetable side dishes (combining protein with fiber), add some meat or cheese to vegetable salads with beans or chickpeas. These combinations improve the absorption of vegetable protein and increase the nutritional content of your diet.

• Limit your intake of processed meat products (sausages, frankfurters, bacon). They contain a lot of salt, saturated fats and nitrates. If you like meat, it is better to cook it yourself – bake a piece of lean beef or chicken. As a snack, instead of sausage, choose a handful of nuts or a boiled egg.

• Drink plenty of water, especially when increasing the proportion of protein in your diet, as this will help reduce the load on your kidneys and improve your metabolism.

By following these guidelines, you will be able to balance your diet so that you get the optimal amount of protein to maintain your health without overloading your body with extra calories and unwanted substances.

Remember that the healthiest approach is variety: include different types of protein foods and combine them with vegetables, fruits, and whole grains for a complete meal.

Infographics

To visualize the information, below is an infographic comparing the protein content of various animal and plant-based products. Animal sources are marked in blue and plant sources in green.

The infographic shows that some foods (e.g., hard cheeses, chicken breast, lean meat) are record-breakers in terms of protein content per 100g.

Plant foods generally contain less protein per unit weight, but by combining different sources (e.g., cereals and legumes) a cumulatively high protein intake can be achieved.

In real nutrition, food portions vary: 100g of nuts is easier to eat than 100g of cheese or dried lentils, so portion sizes are important to consider as well. The infographic helps you compare foods by protein density and plan your diet according to your goals – whether it’s building muscle, losing weight or maintaining overall health.

List of references

1. Carbone J.W., Pasiakos S.M. (2022). The role of dietary plant and animal protein intakes on mitigating sarcopenia risk. Curr Opin Clin Nutr Metab Care, 25(6):425-429​
   pubmed.ncbi.nlm.nih.gov
2. Boff J.C. et al. (2020). Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function. Nutrients, 12(12):3704​
   pmc.ncbi.nlm.nih.gov
3. Naghshi S. et al. (2020). Dietary intake of total, animal, and plant proteins and risk of all-cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies. BMJ, 370:m2412​
   pubmed.ncbi.nlm.nih.gov
4. Kalantar-Zadeh K., Joshi S. (2020). The Effects of High-Protein Diets on Kidney Health and Longevity. Clin J Am Soc Nephrol, 15(3):402-407​
   pmc.ncbi.nlm.nih.gov
5. Koh G. et al. (2020). Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss. J Obes Metab Syndr, 29(3):166-175​
   pmc.ncbi.nlm.nih.gov