Complete vs. incomplete proteins
Understand essential amino acids, protein quality and what to look for on food labels.
What does “complete” mean?
Protein contains amino acids. Nine are essential, meaning we must obtain them through food. A complete protein supplies all nine in adequate proportions. Other protein sources may provide lower proportions of one or more essential amino acids; they still contribute to daily protein intake.
Complete proteins
- Eggs
- Chicken, turkey, beef and pork
- Fish and seafood
- Milk, Greek yogurt and cheese
- Soy foods: tofu, tempeh and edamame
- Quinoa*
Other protein sources
Often lower in one or more essential amino acids:
- Beans, lentils and chickpeas
- Rice, oats, wheat and pasta
- Nuts and nut butters
- Seeds
- Most vegetables
*Quinoa contains all nine essential amino acids but provides less protein per typical serving than foods such as meat, eggs or Greek yogurt.
Why protein quality matters
Muscle and recovery
Protein supplies the amino acids needed to maintain and build muscle and recover from exercise. Total daily intake matters, alongside adequate energy, resistance training and protein quality.
Fullness
Protein generally promotes satiety, although fibre, food volume and other factors also influence how satisfying a meal feels.
Plant proteins count
A variety of plant foods across the day can provide essential amino acids. You do not need to pair complementary proteins at every meal.
“High protein” on the package: look closer
Protein-fortified candy, chips, cookies, bars and other convenience foods are increasingly common. But 20 g of protein on a label does not always mean the same muscle-building value as 20 g from eggs, dairy, meat or whey.
Some products use complete proteins such as whey, milk or soy. Others use collagen or gelatin, which provide less of certain essential amino acids and are less effective as standalone proteins for stimulating muscle protein synthesis. Ingredients, serving size and the overall diet matter.
Adapted from Core Wellness Co. — Complete vs. Incomplete Proteins.