When it comes to fueling your body, protein is one of the most essential nutrients. But not all proteins are created equal. For many people, especially those working on fitness and nutrition goals, it’s important to understand the difference between complete and incomplete proteins and how to make these work in your diet.
Complete vs. Incomplete Proteins: What’s the Difference?
Proteins are made up of smaller building blocks called amino acids. There are twenty different amino acids, nine of which are essential—meaning your body can’t produce them on its own. Complete proteins contain all nine essential amino acids, while incomplete proteins are missing one or more.
Complete proteins are mostly found in animal products like chicken, fish, eggs, and dairy, as well as in some plant sources like quinoa and soy. On the other hand, incomplete proteins are more common in plant-based foods, including grains, nuts, seeds, and certain vegetables.
Why Amino Acids Matter for Your Health
Think of amino acids as puzzle pieces needed to support muscle repair, hormone regulation, immune function, and more. Without the complete set of essential amino acids, your body might miss out on the full benefits protein provides. This is particularly important if you’re looking to gain strength, maintain muscle as you age, or recover effectively from exercise.
How Much Protein Should You Eat?
For most people aiming for fitness and health, a good goal is 0.7 to 1 gram of protein per pound of body weight. Hitting this amount generally provides enough amino acids for your body to work with, which gives you the flexibility to include both complete and incomplete protein sources in your diet without any problem.
For example, if you weigh 150 pounds, aiming for around 105 grams of protein daily will help cover your amino acid needs, leaving room to enjoy a variety of protein sources, whether it’s eggs at breakfast, a chicken salad at lunch, or some collagen in your smoothie. As long as you’re meeting that total intake, you don’t need to stress about getting every amino acid in each meal.
If Your Protein Intake Is Low, Choose Wisely
If you’re not meeting that 0.7 grams per pound target, focusing on high-quality proteins is even more important. Without enough protein, your body has fewer amino acids to work with, so the quality of each protein source matters more. This is where it’s especially beneficial to prioritize complete proteins, like lean meats, dairy, and protein-rich plant options like quinoa, soy, and certain combinations of plant foods (e.g., beans with rice).
Vegetarians and Protein Quality: Getting Your Essential Amino Acids
As a vegetarian, it might take a bit more planning, but you can absolutely meet your amino acid needs with plant-based foods. While individual plant proteins may be incomplete, combining different sources throughout the day can help cover all your bases. Classic combinations, like rice and beans, peanut butter on whole-grain toast, or lentils with quinoa, provide a mix of amino acids that collectively meet your needs.
Practical Tips for Hitting Your Protein Target
Prioritize a Variety of Protein Sources: Including a range of proteins—like chicken, tofu, lentils, eggs, and dairy—helps you cover your amino acid needs naturally.
Focus on Whole Foods First: Whole food proteins are packed with other nutrients (like fiber, vitamins, and minerals) that support overall health. Try to get most of your protein from whole food sources, then supplement with items like protein powders as needed.
Use Collagen and Plant-Based Proteins as Supplements, Not Staples: Collagen is popular for skin and joint health, but it’s an incomplete protein, lacking the amino acid tryptophan. If you’re hitting your daily protein goal, collagen can add to your total intake, but it’s not enough on its own. The same goes for plant-based protein powders unless they’re specifically blended to include all essential amino acids.
Consider Tracking Your Protein Intake: Especially if you’re new to paying attention to protein, tracking your intake (even for a week) can give you insight into whether you’re meeting your protein needs and what adjustments might help.
Plan Ahead, Especially if You’re Vegetarian: Take a little time each week to plan meals that include complementary proteins to cover your amino acid needs. Meal prepping dishes like quinoa and black bean bowls or lentil soups with whole grains can make it easier to hit your protein target without too much hassle.
The Bottom Line: Protein Quality + Quantity = Success
Getting enough protein each day is key to hitting your health and fitness goals, and including a mix of complete and incomplete proteins can keep things balanced and enjoyable. If you’re meeting your total protein needs, enjoy the flexibility to mix in different sources without worrying about amino acid balance in every bite. And if your intake is on the lower side, it’s worth focusing on complete, high-quality proteins or combining plant-based proteins to support your body’s needs.