Among the dietary challenges for vegetarians and vegans, perhaps none is more concerning than the constant quest to get enough protein. It’s hard enough for those on a plant-based diet to compete with the sheer density of protein provided by meat and dairy, but given the need to combine supplemental protein, it seems nearly impossible.
If you are unfamiliar with the concept of incomplete proteins, please read on. Below we’ll discuss what they are, how they vary, and how to combine them to make them complete.
What is protein supplementation?
Protein pairing involves combining plant foods that are missing or low in one or more specific amino acids (the building blocks of protein) to supplement your overall protein intake. There are 20 different amino acids, but only 9 are considered essential. This means your body cannot produce them, so they must be obtained from food.
Foods containing all nine essential amino acids (EAA) have high biological value and are considered “complete proteins.” While all animal-based proteins are complete proteins, few plant-based foods meet this criterion. But you can still get all the EAAs through a combination of plant-based foods. That is Complementarity…complementarity…complementarity – whatever you want to call it!
You can think of amino acids as beads on a protein necklace: by stringing together different numbers and types of beads, your body can create endless possibilities for tissues, hormones, and more. It’s good for you to have as many beads as possible, just in case you need them.
Complete vs. Incomplete Plant Proteins
You can count the number of complete plant proteins on one finger: Currently, soy is the only proven complete plant protein, despite common sense to the contrary. This makes it an ideal source of protein for vegetarians and explains its popularity as a meat substitute.
but you able Get all essential amino acids from plant sources – just a certain dietary balance is required. Legumes (except soybeans), grains, nuts, seeds, and vegetables are incomplete sources of protein because they lack or do not contain enough of one or more EAAs. But together they can form a complete protein profile.
The chart below explains which plant foods are missing which amino acids and how to combine them to get all nine EAAs. For example, rice and beans are a good example of complementary proteins.
| food | missing amino acid | Supplemental protein sources |
| beans | Methionine | Grains, nuts, seeds |
| cereals | Lysine, threonine | beans |
| Nuts and seeds | Lysine | beans |
| vegetable | Methionine | Grains, nuts, seeds |
| corn | Tryptophan, lysine | beans |
Should you also take a protein supplement?
Protein supplements used to be promoted at the same time, but now it’s generally accepted that you can get away with eating them within a day or so. “Vegetarians and vegans don’t need to worry about supplementing food at every meal. Just pursue a balanced diet,” Maguire advises.
How to combine complementary proteins
Even after reading this article, the budget-conscious among us (see what we did there?) may still want to pair complementary proteins. If it makes your protein-counting job easier, complementary protein pairings naturally appear in many traditional cuisines:
- beans and rice
- Peanut Butter and Wheat Bread
- Hummus and pita bread
- Corn Flakes and Bean Dip
- oatmeal and almonds
- Barley and Lentil Soup
Clearly, there are plenty of delicious complementary protein pairings. For those who are considering protein supplementation, here are three rules of thumb:
1. Choose high-protein foods
If you’re following a calorie-restricted diet, it’s a good idea to choose more protein-dense plant-based foods (nuts, seeds, beans, tofu, etc.) to ensure you meet your daily needs without going over your calorie budget. (You should still eat avocados, mushrooms, oatmeal, spinach, broccoli, and kale; they all contain protein, just not as much.)
You also get fiber without adding calories. Win-win.
2. Eat a variety of plant-based proteins
The more varied your diet, the less important protein supplementation is. Diversification can be difficult due to tight budgets. In this case, pair it with some amino acids to form a complementary high-protein food (see picture above).
3. Supplement complete protein
Eggs, Greek yogurt, cottage cheese, and low-fat milk can increase protein intake for some vegetarians. Obviously, they’re not suitable for vegetarians, who can take advantage of organic soy foods like tempeh, tofu and edamame.
Why it’s harder for vegetarians and vegans to get enough protein
High-protein diets are valued among highly active people because protein promotes recovery and improves performance. Consuming protein after exercise can also help stimulate muscle growth and build strength. If you’re cutting back on calories to lose weight, high-protein snacks can help you avoid hunger and preserve muscle mass while losing weight.
Not surprisingly, vegetarians and vegans eat less protein than omnivores. As a group, athletes require more protein than the average person. “Vegan and vegetarian athletes are typically recommended to consume 10 percent more protein than non-vegetarian athletes,” says Krista Maguire, senior nutrition manager at BODi.
This is because plant-based proteins are generally less digestible than animal-based proteins. Therefore, vegetarians and vegans must make smart protein choices to get enough nutrients to achieve their diet and fitness goals.