Protein 101: Why is Protein so Important?

We hear a lot about it, but why is protein so important to a healthy diet? If you’ve ever wondered if you’re eating the correct amount for your goals or you’re getting it from the right sources, this post is for you!

What is it?

Protein is a macronutrient (like carbs and fat). It’s made from smaller building blocks You’ve called amino acids. There are 20 different amino acids. Nine of them are considered ‘essential’ (i.e., they need to come from the diet because our bodies can’t make them). The rest are ‘non-essential’ (i.e., our bodies can make them so we don’t have to get them from our diets under most conditions).

Conditionally essential amino acids are usually made by the body, but in certain circumstances like severe illness or stress, our bodies may not be able to make enough. In those cases, supplementing with these individual amino acids can be helpful. (We would usually only see this in the hospital with patients that have wounds or burns.)

The foods we eat contain varying amounts of protein and amino acids. You may even see some familiar names in the ‘essential’ section below. (Tryptophan, anyone?)

amino acids essential vs non-essential Venn diagram

Animal foods typically contain all of the essential amino acids, making them a “high biological value” protein source. (i.e., We get more bang for our buck with these foods). Plant foods typically contain a variety, but not all of the essential amino acids.

Does this mean that plant foods are a bad source of protein? Absolutely not! Balanced plant-based eating can still give us all of the amino acids we need. Eating a variety of foods is key.

Do we need to combine “complementary” plant-based proteins at each meal to give us all of our essential amino acids? Nope. Again, variety is key. As you eat a wide range of protein-rich foods throughout the day, your body breaks them down into amino acids, then re-assembles them into the complete proteins your body needs.

Why is Protein So Important?

When we think of protein, we usually associate it with building strong muscles. It definitely helps with this, but it also plays so many other roles.

  • Plays a crucial role in building and maintaining healthy tissues – The protein we eat goes to the muscles we typically think of (the skeletal muscles like our biceps) but it also gets used for maintaining other tissues like organs, hair, and skin.
  • Helps us stay full and manage cravings – Digesting foods that contain protein stimulates one of our “fullness hormones” (peptide YY, to be exact) and suppresses our “hungry hormone” ghrelin. (1, 2) Including a source of protein at meals and snacks can help us feel more satisfied after eating and give our meal more staying power. (Goodbye, “hangry” feelings!)
  • Essential for bone health – Calcium gets a lot of attention when it comes to building strong bones, but our bodies also need adequate protein for building bones, especially as we get older. (3) See this video from Yale University for a fantastic explanation of how this occurs!
  • Boosts metabolism – When we eat, our body uses energy to digest food (aka the thermic effect of food, or TEF). The degree of this energy is affected by which macronutrients we eat. Protein has the highest TEF of the macronutrients (our body has to work harder to break it down), which can increase our metabolic rate. (4) Pretty cool!
oatmeal and dry beans spilling out of jars

How Much Do You Need?

Ah, this is where the debate usually starts. Some experts tell you to load up, while others tell you that you’re probably eating too much. Who should you believe? I’ll approach this from two angles – science AND real-life – because we should take both into account when we’re making nutrition choices.

1. Science

The RDA (or recommended daily allowance) for most people is 0.8 grams of protein per kilogram of bodyweight. Example time! A 160 lb woman weighs 72.7 kilograms, multiplied by 0.8, this would give us about 58.2g of protein per day. That’s equivalent to a 4oz chicken breast (35g), a container of yogurt (17g), and 1 large egg (6g). Doesn’t seem like a lot, right?

Per the National Institutes of Health, the RDA is the recommended amount of the nutrient that is sufficient enough to meet the needs of 97-98% of people. (5) Sufficient (good enough) doesn’t always mean optimal.

The ideal amount of protein for each person should be individualized. Your needs depend on your age, weight, injuries, illness, some medical conditions, physical activity level, and your goals. After re-examining the research used to make the RDA, some researchers believe that the RDA for protein should be higher (1 gram per kilogram of body weight). (6) (This would give our 160 lb woman 72.7 grams of protein instead of 58.2 – that’s about a cup of chickpeas more! Can you imagine how much more full and satisfied you would feel?) This is a good place to start for most adults who aren’t physically active.

If you’re active, you’ll need more protein for recovery and performance. 1.2-2.2 grams per kilogram of body weight is appropriate in many cases. (7,8)

For a thorough review of the research and recommendations on protein intake for just about any goal or life stage – see the following article from Examine. For a more fitness and body-composition focused tool for calculating your protein intake, see this article from WorkoutCave.

2. Real-life

If you’re a details person, it can be helpful to have the numbers I mentioned above. Let’s get real, though, tracking and number-crunching isn’t a great fit for everyone. It’s important to know if you’re getting enough nutrition during your day without having to rely on calculations or apps.

My suggestion – aim to include a source of protein at each meal and snack. Yep. That’s it.

Prioritizing protein throughout the day will help you stay full and ensure you’re meeting your needs. You can always add more if you find that you’re really hungry or you’re recovering from a workout, illness, or injury.

chart with protein needs for different people

Sources (Are some better than others?)


This includes chicken, turkey, beef, pork, lamb, and game meats. These are high-quality options because they contain a complete collection of the essential amino acids that our bodies need.

Fish + Seafood

Commonly eaten proteins of the sea (and lakes and rivers) include salmon, tuna, mackerel, halibut, trout, bass, shrimp, clams, crab, and oysters, but there are so many other options available.


Yep, pretty self-explanatory!


My personal favorite category includes milk, cheese, yogurt, kefir, and cottage cheese.

A note on plant-based milk alternatives – these can be a good source of protein but check the label! Some popular varieties like almond and coconut products are very low in protein unless they are fortified. Soy products tend to be higher in protein, as are blends made from multiple types of non-dairy products and/or supplemental pea protein.

A note on non-dairy cheeses – these are often made from soy, nuts, seeds, or a combination of these foods.


Tofu, tempeh, seitan, edamame, meat alternatives (can also contain other foods from this list), TSP (textured soy protein, aka TVP), and soybeans all fall into this category. Have you ever heard that you should avoid soy? Read this first.

Nuts + Seeds

Hemp seeds, pumpkin seeds, peanuts, almonds, pistachios, sunflower seeds, flax seeds, chia seeds, sesame seeds, cashews, walnuts, hazelnuts, pecans, macadamia nuts, and nut/seed butter all contain protein

Keep in mind that all foods are made up of a variety of nutrients. Just because a food is a good source of protein, contains protein, or is primarily made of protein does not mean the food only gives us protein. For example, nuts contain protein, but they also contain fat and fiber.

Example time! You’d have to eat a whole cup of almonds to get the same amount of protein you’d get from 6 oz of tempeh! (To compare, the almonds would give you 822 calories, 31g carbs, 70.7g fat, and 30g protein. The tempeh would give you 322 calories, 16g of carbs, 18g fat, and 32g protein.) Neither is bad – one is just a more efficient protein source than the other. The same concept applies to veggies. Although broccoli contains some protein we’d have to eat a ton of them to get as much protein as turkey or tofu would give us.


Most veggies aren’t a great source of protein, but some contain a bit more protein than the rest (about 4-5g per serving), including broccoli, brussels sprouts, and asparagus.

Whole grains

They’re not just carbs, friends! Whole grains also contain a fair amount of protein. Some options are whole grain bread, pasta, brown rice, barley, quinoa, oats, farro, and popcorn.


AKA beans, peas, and lentils. These nutritional powerhouses also contain some carbohydrates (including a healthy dose of fiber) but they can be a good way to get protein, too. Some other foods that fall under this category are chickpeas, black beans, kidney beans, pinto beans, and white beans.

chart with food sources of protein

What about protein powders? Protein powders are processed from a variety of sources (whey protein from dairy, peas, hemp, soy, and collagen, to name a few). These can be a good option if you need a convenient source of protein that doesn’t require much preparation or you’re having trouble meeting your protein needs on a regular basis. Protein powders can be added to smoothies, oatmeal, shakes, and desserts. The downside? Protein powders won’t always provide you with the same eating experience and a wider spectrum of nutrients that whole foods can.

Should you choose animal-based or plant-based protein sources? That choice is a personal one, and it is totally up to you. You can meet your protein needs on an omnivorous diet, a pescetarian diet, a vegetarian diet, or a vegan diet. No matter your diet preference, the key is variety. For omnivores and pescetarians, aim to eat fish at least twice per week and at least one meal with a plant-based protein per week. For vegetarians and vegans, make sure to switch up your protein sources so you get a broad spectrum of nutrients and avoid food ruts.


  7. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic PerformanceMed Sci Sports Exerc. (2016)

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.