What Makes a Protein "Complete"?
Protein, a vital macronutrient, is comprised of amino acids. While the body produces 11, nine are essential and must be obtained through diet. A protein source is complete if it provides all nine essential amino acids in adequate amounts. Although animal products were traditionally seen as the primary source of complete proteins, we now recognize several plant-based options that fit this criteria.
Leading the Pack: Top Complete Plant Proteins
Several plant proteins offer all nine essential amino acids. Incorporating these into your diet is a simple way to meet your protein requirements.
Soy Products
Soy is a well-known complete plant protein. Its various forms include tofu, tempeh, and edamame, each offering a good source of protein. For example, a 3-ounce serving of firm tofu contains about 8 grams of protein, while a similar serving of tempeh provides approximately 11 grams. Edamame offers around 8 grams of protein per half-cup serving.
Quinoa
Quinoa, a pseudocereal, is recognized for having all nine essential amino acids. A cup of cooked quinoa contains approximately 8 grams of protein and is also rich in fiber, magnesium, and iron.
Hemp Seeds
Hemp seeds are another complete protein source. Three tablespoons provide about 10 grams of protein and are rich in omega-3 and omega-6 fatty acids. They can be easily added to various dishes.
Other Excellent Complete Sources
Chia seeds, buckwheat, amaranth, spirulina, and nutritional yeast are also considered complete plant protein sources. Chia seeds offer 4 grams of protein per two tablespoons, along with omega-3s and fiber. Buckwheat and amaranth are gluten-free pseudocereals with complete protein profiles. Spirulina is a nutrient-dense algae, and nutritional yeast provides a savory flavor and is often fortified with B12.
The Complementary Protein Approach
The idea that vegans must combine specific plant proteins at every meal to form complete proteins is outdated. The body effectively uses amino acids from various sources consumed throughout the day to create complete proteins. A diverse diet is sufficient. Examples of traditional complementary pairings include rice and beans, hummus and pita, and peanut butter on whole grain toast.
Comparing Complete Plant Proteins
| Protein Source | Protein per serving | Key Nutrients | Common Uses |
|---|---|---|---|
| Tofu (Firm) | ~8g per 3oz | Calcium, Iron, Potassium | Scrambles, stir-fries, baking |
| Tempeh | ~11g per 3oz | Fiber, Iron, Probiotics | Grilling, curries, sandwiches |
| Quinoa (Cooked) | ~8g per cup | Fiber, Magnesium, Iron | Salads, bowls, side dish |
| Hemp Seeds | ~10g per 3 tbsp | Omega Fatty Acids, Fiber | Topping for salads, yogurt, smoothies |
| Chia Seeds | ~4g per 2 tbsp | Omega Fatty Acids, Calcium | Puddings, smoothies, baking |
| Nutritional Yeast | ~8g per 1/4 cup | B vitamins (B12 fortified) | Cheesy sauces, popcorn topping |
How to Build a Complete Plant-Based Diet
Achieving complete protein nutrition on a plant-based diet is simple by eating a variety of foods. Focus on diversifying your protein sources throughout the day, including legumes, grains, nuts, and seeds. Incorporating complete proteins like soy products regularly is helpful. Snacking on options like edamame or nutritional yeast on popcorn can also contribute to your protein intake. Prioritizing whole, unprocessed plant foods ensures a broader range of amino acids and nutrients.
The Bottom Line
You can easily obtain all essential amino acids on a plant-based diet by including complete protein sources like soy, quinoa, and hemp seeds, and maintaining a diverse diet. The key is variety over the course of the day. For more information on the nutritional science of plant-based foods, authoritative resources such as the National Institutes of Health provide in-depth details.
