What Determines a High Protein Food?

December 26, 2025 •

4 min read

According to the Food and Drug Administration (FDA), a food that provides 20% or more of the daily value for protein is considered a high protein source. However, this simple metric doesn't tell the whole story, as other crucial factors also determine what makes a high protein food truly beneficial for your body.

Quick Summary

This guide breaks down the complex science of protein quality, exploring factors like amino acid composition, digestibility, and bioavailability that define what determines high protein beyond basic nutritional labels.

Key Points

Amino Acid Profile: High protein foods are defined by their complete amino acid profile, containing all nine essential amino acids.
Digestibility and Bioavailability: How well the body can digest and absorb protein is a critical factor, with metrics like PDCAAS assessing true protein quality.
Macronutrient Balance: The concentration of protein relative to other macronutrients (fats and carbs) helps determine if a food is a true protein powerhouse.
Source Matters: Animal-based proteins are typically complete and more digestible, while a variety of plant-based foods can be combined to form a complete protein profile.
Varied Diet: Eating a wide range of protein sources is the best way to ensure all daily essential amino acid needs are met.
FDA Standard: A food is considered a high source of protein if it provides 20% or more of the daily value per serving.
Not Just the Grams: A higher gram count doesn't automatically mean higher quality; the type of amino acids and how the body processes them are more important.

Understanding Protein Quality: More Than Just Grams

When evaluating a food's protein content, most people focus solely on the number of grams per serving. While useful, this is a very basic measure. A food with 20 grams of protein isn't necessarily a better source than one with 15 grams. The true measure of a high-quality, high protein food depends on several scientific factors that relate to how your body processes and utilizes that protein. This article delves into those key determinants, helping you make more informed dietary choices.

The Amino Acid Profile: Complete vs. Incomplete Proteins

Proteins are made up of building blocks called amino acids. There are 20 amino acids, nine of which are considered "essential" because the body cannot produce them and must obtain them from food. A protein source that contains all nine essential amino acids in sufficient quantities is called a "complete protein." Foods from animal sources, such as meat, fish, eggs, and dairy, are typically complete proteins. Some plant-based foods, including soy, quinoa, and amaranth, are also complete proteins.

On the other hand, "incomplete proteins" lack or are low in one or more essential amino acids. Most plant-based proteins, such as beans, nuts, and grains, fall into this category. However, this doesn't mean they are poor sources of protein. By eating a variety of plant-based foods throughout the day, vegetarians and vegans can easily get all the essential amino acids their bodies need. For example, combining rice (low in lysine) with beans (low in methionine) creates a complete protein profile.

Digestibility and Bioavailability: What Your Body Can Use

How well your body can break down and absorb the amino acids from a food is a critical factor in determining its protein quality. This is known as digestibility. A food may have a high protein content, but if the body cannot effectively digest it, much of that protein is wasted. For example, animal proteins are generally more digestible than plant-based proteins, which often contain fiber and antinutrients that can interfere with absorption.

Bioavailability refers to the proportion of the absorbed amino acids that your body can actually use. Several metrics have been developed to measure this, such as the Protein Digestibility Corrected Amino Acid Score (PDCAAS), which is a globally recognized standard. The PDCAAS score is a more advanced method than simply counting grams, as it factors in both the amino acid profile and digestibility. Foods with a PDCAAS score of 1.0 (the highest possible) are considered excellent, high-quality protein sources for humans.

Comparing High-Protein Food Sources

To illustrate the factors that determine high protein, here is a comparison table of common protein sources based on their amino acid profile, digestibility, and overall quality.


Food Source	Protein Type	Amino Acid Profile	Digestibility	Overall Quality	Recommended For
Whey Protein	Animal (Dairy)	Complete	Excellent	Highest	Athletes, muscle building
Casein Protein	Animal (Dairy)	Complete	Good (slow release)	High	Satiety, overnight muscle repair
Eggs	Animal	Complete	Excellent	Highest	General health, muscle building
Chicken Breast	Animal	Complete	Excellent	Highest	Lean muscle growth
Soy Protein	Plant	Complete	Excellent	High	Vegetarians, vegans, general health
Beef	Animal	Complete	Excellent	High	Iron source, muscle growth
Lentils	Plant	Incomplete*	Good	Moderate	Fiber, complex carbs, balanced diet
Beans	Plant	Incomplete*	Good	Moderate	Fiber, complex carbs, balanced diet

*Note: Incomplete plant proteins can be combined to form a complete protein profile over the course of a day.

Considering Macro Composition

The surrounding macronutrients can also influence how a food is perceived as "high protein." While a food might contain a significant amount of protein, it may be dominated by fat or carbohydrates, changing its nutritional profile. For example, almonds contain protein, but they are primarily a source of fat. Similarly, black beans contain protein, but are richer in carbohydrates. A truly high protein food should have a greater concentration of protein compared to its other macros.

Conclusion

Determining what constitutes a high protein food goes far beyond a simple glance at a nutritional label. While the total number of grams is a starting point, a comprehensive evaluation must consider the food's complete amino acid profile, its digestibility, and its overall macronutrient composition. For optimal health and muscle development, a varied diet that incorporates complete, highly bioavailable protein sources—whether from animal or a combination of plant sources—is key. Making smart protein choices based on these determinants ensures that your body is getting the highest quality building blocks it needs to thrive.

For more detailed information on protein quality assessment, explore the standards set by the World Health Organization and the Food & Agriculture Organization.

Frequently Asked Questions

Complete proteins contain all nine essential amino acids in sufficient quantities, while incomplete proteins are low or missing one or more essential amino acids. Animal products and some plant foods like soy and quinoa are complete, whereas most other plant sources are incomplete.

Yes. Animal proteins are generally more easily digested and have higher bioavailability, meaning your body can use more of the absorbed amino acids. Plant proteins can be less digestible due to fiber content, but combining different plant sources throughout the day can compensate for this.

Vegetarians and vegans can get all essential amino acids by eating a varied diet that includes a mix of different plant-based protein sources, such as combining legumes and grains (like rice and beans) over the course of a day.

Not necessarily. While the amount of protein is important, the quality is determined by the food's amino acid profile, digestibility, and bioavailability. A food with fewer grams of highly digestible, complete protein may be more beneficial than a food with more grams of incomplete, less digestible protein.

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is a metric used to measure protein quality. It considers both the amino acid profile and the protein's digestibility, with a score of 1.0 representing the highest quality.

Generally, cooking methods like boiling, baking, and grilling do not significantly diminish the nutritional quality of protein. However, excessive heat can cause a slight denaturation, but this is usually not a major concern for dietary intake.

No. While lean meats and whey protein are high in protein and low in fat, many foods like almonds or certain cuts of beef are high in both protein and fat. The overall macronutrient balance is important for understanding the food's full nutritional profile.