What’s the Difference Between Complete and Incomplete Proteins?

Protein is widely known for its role in helping our bodies build muscle mass, but have you ever thought about what protein is made from and why it’s so important in our daily lives? Let’s take a good look at this important element of nutrition and wellness. We’ll discuss where protein comes from, what the differences between a complete protein and incomplete protein is, how to choose high protein foods and so much more.

Protein 101

Protein is one of the three key macronutrients we need each day. It helps build muscle mass, builds and repairs tissue and is a component of our bones, cartilage, skin, hair, nails, blood, muscles, hormones and enzymes. Proteins are needed for many of our body’s functions and cell structures – they’re literally the building blocks of life.

Proteins are compounds that consist of carbon, hydrogen and nitrogen arranged as strands of amino acids. Proteins can consist of a single amino acid or multiple amino acids, and the amino acids are categorized as essential and non-essential. Essential amino acids are those your body cannot create and must get through food; non-essential amino acids are ones your body can create on its own.

Protein can be acquired from both animal and plant foods and can be considered “complete” or “incomplete.” Let’s break down the differences and get to know their sources.

What is a complete protein?

A complete protein, also referred to as a “whole protein,” is a protein that contains all nine essential amino acids. Complete protein comes mainly from animal-based sources. A few complete protein examples include eggs, dairy, fish, poultry, and meat. Complete protein foods can also come from plant sources, including quinoa, buckwheat, seitan, mycoprotein (Quorn), soy and Ezekiel bread. Chia seeds, hemp seeds and pumpkin seeds technically contain all nine essential amino acids but aren’t considered a complete protein due to their low levels of the amino acid lysine and methionine.

What is an incomplete protein?

An incomplete protein is a protein that does not contain all nine essential amino acids. These proteins may contain many essential amino acids, but if one amino acid is missing or the level is too low, it is considered incomplete. Incomplete protein sources are mostly plant-based sources, including nuts, seeds, beans, legumes, whole grains, tofu, rice and vegetables.

Incomplete proteins can be paired together at meals or throughout the day to make a complete protein. This is called complementary protein pairings; however, to work effectively, the proteins cannot be missing the same essential amino acids. Some examples of these pairings include the classic peanut butter sandwich, rice and beans, hummus and pitas, beans and tortillas, and pasta and peas. Our bodies can also store essential amino acids, which gives us even more flexibility. If we consume an incomplete protein without a complement, our body can supplement the missing amino acid from the body’s stores.

Protein needs

Each person’s daily protein requirements are extremely individualized and vary based on many factors. Age, gender, and activity levels are just a few things that play a role in how much protein our bodies need. The minimum standard recommendation is 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound. Since we need to incorporate a variety of protein sources into our diet, a good rule of thumb is to include something that provides protein with each meal and snack. This ensures we get a nice balance of complete proteins, incomplete proteins, vitamins, and minerals every day.

Wondering if you’re consuming adequate protein amounts? Schedule a Telenutrition appointment and connect with a registered dietitian for guidance and personalized nutrition advice. Check out more healthy lifestyle tips.

_{Disclaimer: This information is educational only and is not meant to provide healthcare recommendations. Please see a healthcare provider.}