What are the best types of proteins? A Nutrition Diet Guide

October 28, 2025 •

6 min read

More than half of the protein needed for a healthy diet is found in a variety of foods, from both animal and plant sources, and not just in meat. The question of what are the best types of proteins is not about one superior source, but about understanding the different qualities and benefits of each.

Quick Summary

An overview of protein types, distinguishing between complete and incomplete sources found in animal and plant foods. It highlights factors like amino acid profile, digestibility, and overall nutritional content.

Key Points

Complete vs. Incomplete: Complete proteins (animal, soy, quinoa) have all essential amino acids; incomplete (most plants) lack one or more but can be combined throughout the day.
Animal Protein Advantages: Generally complete and highly bioavailable, making them very efficient for muscle synthesis, especially fast-digesting whey protein.
Plant Protein Advantages: Rich in fiber, antioxidants, and phytochemicals, and often lower in saturated fat, supporting heart and gut health.
Consider the 'Protein Package': Evaluate the overall nutrient profile of a protein source, not just the amino acid content. Leaner animal sources and diverse plant foods offer superior health benefits.
Variety is Key: Eating a mix of different protein sources, from both animal and plant kingdoms, is the best way to ensure you receive a full spectrum of amino acids and associated nutrients.
Distribution of Intake: Spreading protein consumption across multiple meals, rather than one large sitting, maximizes absorption and benefits like muscle protein synthesis.

Protein is a crucial macronutrient composed of amino acids, which are the building blocks for countless structures and functions in the human body. Your body needs 20 different amino acids, nine of which are essential because the body cannot produce them on its own. The quality of protein is determined by its amino acid profile and its digestibility. For a balanced diet, it's essential to understand the difference between complete and incomplete proteins and to incorporate a variety of sources.

The Role of Complete vs. Incomplete Proteins

Proteins are classified based on their amino acid content. A 'complete' protein contains all nine essential amino acids in sufficient quantities, while an 'incomplete' protein lacks one or more of them.

Complete Proteins: Primarily derived from animal sources, such as meat, dairy, eggs, and fish. A few plant-based sources, notably soy and quinoa, are also considered complete proteins. For those on a vegan or vegetarian diet, these plant-based complete proteins are especially valuable.

Incomplete Proteins: Most plant-based proteins, including legumes, grains, nuts, and seeds, are incomplete. However, by consuming a variety of these sources throughout the day, individuals can easily meet their essential amino acid needs. It was once thought that these sources needed to be paired in the same meal, but this is now known to be unnecessary. Examples of complementary pairings that naturally form a complete protein profile include rice and beans or hummus and pita bread.

Excellent Animal-Based Protein Sources

Animal products are renowned for their high protein quality and bioavailability, meaning the body can easily digest and utilize their amino acids.

Lean Meats and Poultry

Chicken and Turkey Breast: These white meats are excellent sources of lean protein, providing all essential amino acids without high levels of saturated fat. They are staples for muscle building and weight management.
Lean Beef and Pork: Opt for leaner cuts, such as sirloin or tenderloin, to get high-quality protein with less saturated fat. The red meat from these sources provides valuable nutrients like iron and zinc.

Fish and Seafood

Salmon and Tuna: Fatty fish like salmon and lake trout are rich in omega-3 fatty acids, which are beneficial for heart health, in addition to being high in protein. Canned tuna is a convenient and cost-effective protein source.
Shellfish: Shrimp, crab, and other shellfish also provide a good dose of lean protein.

Dairy and Eggs

Eggs: A single egg contains about 6 grams of complete protein along with vitamins, minerals, and healthy fats. Both the yolk and white are nutritious, debunking the old myth about avoiding yolks due to cholesterol concerns.
Greek Yogurt and Cottage Cheese: These dairy products are high in protein and calcium. Plain, low-fat versions are recommended to limit saturated fat and added sugars. Greek yogurt and cottage cheese contain both fast- and slow-digesting proteins (whey and casein).
Whey and Casein Protein Powders: These popular supplements are derived from milk. Whey digests quickly, making it ideal for post-workout muscle repair, while casein digests slowly, providing a sustained release of amino acids, often preferred before bed.

High-Quality Plant-Based Protein Sources

Plant-based diets offer unique health benefits, including high fiber and antioxidant content, which contribute to better heart health and overall wellness.

Soy Products

Tofu, Tempeh, and Edamame: Soybeans are one of the few plant sources that are complete proteins. Tofu is made from coagulated soy milk, while tempeh is fermented, giving it a firmer texture. Edamame are young soybeans and are a complete protein source rich in fiber.
Soy Milk and Protein Isolate: Soy milk is a dairy alternative with comparable protein content, while soy protein isolate powder offers a concentrated dose for supplements.

Legumes, Nuts, and Seeds

Lentils and Beans: A staple in many diets, legumes are excellent, affordable sources of protein and fiber. A cup of cooked lentils provides around 18 grams of protein.
Nuts and Seeds: Almonds, pistachios, chia seeds, and hemp seeds are packed with protein, fiber, and healthy fats. They can be added to salads, oatmeal, or enjoyed as a snack.

Whole Grains and Vegetables

Quinoa: This grain is a complete protein, making it an excellent choice for plant-based diets.
Other Grains: While lower in protein, whole grains like oats, brown rice, and millet contribute to overall daily protein intake.
Protein-rich Vegetables: Vegetables such as broccoli, peas, and spinach contain more protein than you might expect, especially when consumed in larger quantities.

The Importance of the Protein "Package"

The source of your protein is just as important as the quantity. The "protein package" refers to all the other nutrients that come along with your protein, such as fats, fiber, vitamins, and minerals.

Animal Protein Packages: Can be high in complete proteins but some, like fatty red meat, also come with high saturated fat. Prioritizing lean cuts and fish provides a healthier package. Dairy options like low-fat Greek yogurt offer calcium and probiotics.
Plant Protein Packages: Tend to come with a bonus of fiber, antioxidants, and less saturated fat. This is one reason why replacing red meat with plant-based protein sources is linked to lower cardiovascular disease risk.

A Comparison of Protein Sources


Feature	Animal-Based Proteins	Plant-Based Proteins
Amino Acid Profile	Complete (all 9 essential amino acids).	Most are incomplete, but soy, quinoa, and a few others are complete.
Digestion Speed	Varies by source (e.g., whey is fast, casein is slow).	Varies, can be slower due to fiber content (e.g., legumes).
Nutrient Density	High in B12, heme-iron, and zinc.	Higher in fiber, antioxidants, and beneficial phytochemicals.
Fat Profile	Can be high in saturated fat (leaner cuts are healthier).	Generally lower in saturated fat, rich in unsaturated fats (nuts, seeds).
Best for Muscle Gain	Often considered superior per gram for muscle synthesis, especially whey.	Effective, but may require consuming a higher total volume or combining sources.
Impact on Health	High consumption of red/processed meat linked to increased disease risk.	Associated with lower risk of chronic diseases and better cardiovascular health.

How to Choose the Best Protein for You

Determining the 'best' protein is a highly individual process that depends on your dietary preferences, health goals, and specific needs. Whether you follow an omnivorous, vegetarian, or vegan diet, a diverse intake is the most effective strategy for optimal nutrition.

For the Omnivore: Focus on lean meats, a variety of fish (especially fatty ones), eggs, and dairy. Moderating red meat and avoiding processed meats is key for heart health. Incorporating plant proteins like lentils, beans, and nuts can further diversify your nutrient intake and improve overall health.
For Vegetarians and Vegans: It's important to consume a wide range of plant-based sources throughout the day to ensure all essential amino acids are covered. Relying on staples like soy products (tofu, tempeh), legumes, whole grains like quinoa, and a variety of nuts and seeds will provide a complete amino acid profile.
For Athletes and Active Individuals: The timing of protein intake, especially around workouts, can be important. Fast-absorbing whey protein can aid post-exercise muscle repair, while a mixed diet with consistent protein can support long-term muscle synthesis. For plant-based athletes, strategic combinations and complete plant proteins like soy and quinoa are vital.

Conclusion

Ultimately, there is no single "best" type of protein; the most effective approach is to consume a variety of high-quality protein sources from both animal and plant origins, as part of a balanced diet. By considering the completeness, digestibility, and overall nutrient package of different proteins, you can make informed choices to meet your unique health and fitness goals. Focusing on whole, unprocessed foods and diversifying your sources is a winning strategy for maximizing nutritional benefits and supporting your long-term health. For further reading on the science behind proteins and health, the Harvard T.H. Chan School of Public Health offers an excellent resource on its Nutrition Source website.

Frequently Asked Questions

No, plant-based proteins are not necessarily inferior. While most are 'incomplete,' containing less of one or more essential amino acids, you can easily obtain all necessary amino acids by eating a variety of plant proteins throughout the day. Many plant proteins also offer additional health benefits, such as fiber and antioxidants, which animal proteins lack.

Whey and casein are both milk proteins, but they differ in their digestion speed. Whey is a 'fast' protein that digests quickly, making it ideal for post-workout recovery. Casein is a 'slow' protein that forms curds in the stomach, providing a gradual, sustained release of amino acids, which can be beneficial before sleep or periods of fasting.

To get enough protein on a vegetarian diet, focus on a wide variety of sources. Include complete plant proteins like soy products (tofu, tempeh) and quinoa, and combine different incomplete proteins throughout the day, such as beans and rice, or nuts and seeds.

For healthy individuals, moderate protein intake is not harmful. However, excess protein beyond what the body needs is excreted, and in cases of pre-existing kidney or liver conditions, very high protein intake may pose risks. It's best to consult a healthcare professional regarding specific concerns.

For muscle gain, whey protein is often highlighted for its fast absorption and high leucine content, which kickstarts muscle protein synthesis. However, total daily protein intake and consistent resistance training are the most significant factors for muscle growth, and a mixed diet with various protein sources works effectively.

The 'protein package' refers to all the other nutrients that come along with a protein source, including fats, carbohydrates, fiber, vitamins, and minerals. Choosing a healthy protein package means selecting sources that offer beneficial accompanying nutrients, like fiber in beans or omega-3s in fish, and minimizing those with unhealthy additions, like saturated fat in processed meats.

The human body has a limited capacity to absorb protein at once, with fast-digesting proteins like whey being absorbed at around 8–10 grams per hour. It is far more effective and beneficial to distribute your protein intake throughout the day across multiple meals to maximize absorption and ensure a steady supply of amino acids.