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How to Combine Incomplete Proteins to Make a Complete Protein

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4 min read

According to the Cleveland Clinic, a food is considered a complete protein when it contains all nine essential amino acids that our bodies cannot produce. Fortunately, you don't need to rely solely on animal products to get them; you can easily combine incomplete proteins from plant sources to create a complete protein profile. This guide will show you how to combine incomplete proteins to make a complete protein through smart food pairings.

Quick Summary

This guide explains the principles of protein complementation, outlining which plant-based foods to pair to create a complete amino acid profile. It covers the essential amino acids, provides numerous meal examples, and debunks common myths about needing to combine foods at every single meal.

Key Points

  • Essential Amino Acids: The body needs nine essential amino acids from food, which are the building blocks of protein.

  • Protein Complementation: Pairing incomplete proteins from different plant sources provides all nine essential amino acids.

  • Daily Variety is Key: You don't need to combine proteins in every meal; a varied diet over 24 hours is sufficient.

  • Common Combinations: Grains with legumes (rice and beans), nuts/seeds with legumes (hummus with sesame seeds), and whole grains with nuts/seeds (oatmeal with walnuts) are effective pairings.

  • Plant-Based Benefits: Combining plant proteins offers not just complete amino acids but also fiber, vitamins, and other nutrients.

  • Simple Meal Ideas: Easy examples include peanut butter on whole wheat toast, lentil soup with bread, and bean and rice tacos.

  • Dietary Flexibility: Modern nutritional understanding promotes flexibility, so you don't need rigid meal planning to meet your protein needs.

In This Article

Understanding the Building Blocks: Amino Acids

Proteins are fundamental to our body's functions, playing a role in everything from repairing tissues to regulating hormones. They are composed of smaller units called amino acids. The human body requires 20 different amino acids to function properly. Of these, nine are considered “essential” because our bodies cannot produce them and we must get them from our diet.

  • Essential Amino Acids: Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
  • Non-Essential Amino Acids: The other 11 amino acids that our bodies can produce on their own.

The Difference Between Complete and Incomplete Proteins

A food is categorized as a complete protein if it contains all nine essential amino acids in sufficient amounts. Most animal products, such as meat, poultry, eggs, and dairy, are considered complete proteins.

In contrast, incomplete proteins are typically plant-based foods that lack or are low in one or more of the essential amino acids. For example, grains are often low in lysine, while legumes are low in methionine.

The Concept of Complementary Proteins

To compensate for the missing or low amino acids in incomplete proteins, you can combine different plant-based foods. The classic advice used to be that you needed to pair these proteins in the same meal, but modern nutrition science has shown that it is sufficient to consume a variety of protein sources throughout the day. The body has a storage pool of amino acids it can draw from to form a complete protein when needed.

Common Pairings to Combine Incomplete Proteins

Creating complete proteins from plant sources is often intuitive, as many traditional dishes already feature these perfect pairings.

Legumes + Grains

  • Examples: Rice and beans, lentil soup with whole-grain bread, peanut butter on whole wheat toast.
  • Why it works: Grains provide the amino acid methionine, which legumes typically lack, while legumes provide lysine, which grains are often low in.

Legumes + Nuts/Seeds

  • Examples: Hummus (chickpeas) with a topping of sesame seeds, a salad with chickpeas and sunflower seeds.
  • Why it works: Legumes provide a good source of lysine, while nuts and seeds are rich in sulfur-containing amino acids.

Grains + Nuts/Seeds

  • Examples: Oatmeal with walnuts, pasta with pine nuts.
  • Why it works: Nuts and seeds complement the amino acid profile of grains, particularly by providing essential fatty acids alongside the protein.

Dairy + Legumes/Nuts/Seeds

  • Examples: Macaroni and cheese, yogurt with nuts.
  • Why it works: Dairy is a complete protein, but pairing it with plant-based incomplete proteins adds variety and additional nutrients.

Creating a Varied Diet for Complete Protein Intake

Instead of focusing on combining proteins at every single meal, a broader strategy is to ensure dietary variety throughout the day. By consuming a wide range of plant foods, including legumes, whole grains, nuts, seeds, and vegetables, you will naturally meet your needs for all essential amino acids over a 24-hour period.

Table: Complete vs. Incomplete Protein Comparison

Feature Complete Proteins Incomplete Proteins
Essential Amino Acids Contains all nine in sufficient amounts. Lacks or is low in one or more essential amino acids.
Primary Sources Animal products (meat, eggs, dairy), soy, quinoa. Plant-based foods (legumes, nuts, grains, most vegetables).
Need for Combination Not required for a complete profile. Can be combined with other incomplete proteins to achieve a complete profile.
Nutrient Density Often rich in B vitamins and iron. Typically higher in fiber, vitamins, minerals, and antioxidants.
Environmental Impact Generally requires more resources for production. Often more environmentally friendly to produce.

Sample Meal Ideas for Combining Incomplete Proteins

  • Breakfast: Oatmeal topped with a variety of nuts and seeds.
  • Lunch: Hummus and whole wheat pita with a side salad.
  • Dinner: Black bean and rice tacos with a side of corn salsa.
  • Snack: Peanut butter on whole-grain toast.

Conclusion

The notion that you must meticulously combine specific plant foods at each meal to get complete protein has been largely debunked by modern nutritional science. The key is dietary variety. By eating a diverse range of plant-based foods like legumes, grains, nuts, and seeds throughout the day, your body will naturally acquire all the essential amino acids it needs. This makes it simple and enjoyable to meet your protein requirements on a plant-based diet. A balanced, varied diet ensures you gain the benefits of both incomplete and complete proteins, supporting your overall health and wellness.

References

Frequently Asked Questions

Incomplete proteins are sources of protein, typically plant-based, that are low in or lack one or more of the nine essential amino acids that our bodies cannot produce on their own.

No, this is a common misconception. The body maintains a pool of amino acids throughout the day, so as long as you eat a variety of protein sources over the course of a day, you will get all the essential amino acids you need.

Some classic pairings include grains with legumes (like rice and beans), legumes with nuts or seeds (hummus with pita), and whole grains with nuts (peanut butter on whole wheat toast).

No, incomplete proteins are not less healthy. Many plant-based incomplete proteins are packed with other beneficial nutrients like fiber, vitamins, and minerals. A diet rich in a variety of these foods is very healthy.

The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Soy is one of the few plant-based sources that is naturally a complete protein. Foods made from soy, such as tofu, tempeh, and edamame, contain all nine essential amino acids.

Yes, absolutely. By eating a varied and balanced diet that includes a wide range of legumes, grains, nuts, seeds, and vegetables throughout the day, vegans can easily meet all their essential amino acid needs.

No, some plant proteins like soy, quinoa, and buckwheat are considered complete proteins, containing all nine essential amino acids.

References

  1. 1
    Incomplete Proteins
  2. 2
    What are complementary proteins, and how do we get them?
  3. 3
    Complete Protein Foods—Plus How to Combine Incomplete...
  4. 4
    Complete vs. Incomplete Proteins and Examples
  5. 5
    Complete Protein | Definition, Examples & Sources

Related Topics:

#plant-based protein #complete proteins #amino acids #vegetarian diet #vegan nutrition #complementary proteins #incomplete proteins #protein combining

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice.