The Definitive Guide To The Cleanest Plant-Based Protein Sources


Whether you call it being a vegetarian, a vegan, or WFPB (whole-food plant-based), there are many reasons people try switching their diet to one centered around plants rather than around animal products. Some people do it for the perceived health benefits, to support the environment, or for a combination of reasons.

Whatever your reasons, there is no denying that in our current society, not eating any type of animal products or limiting them drastically is a huge lifestyle change. It’s not easy to avoid animal products all the time, and many people have questions, like “Will I be able to go out to restaurants?” “What will my friends and family think?”; “What can I and can’t I eat?” But the the most important question, from my perspective as a functional medicine practitioner, should be: Is this the right diet for my health?

I see many people become vegan, vegetarian, or just more plant-centric as a way to be healthier and manage chronic health problems - after all, conventional wisdom tells us that vegetables are good for us, and that is true. However, after many years of clinical and personal experience, I have seen where conventional vegan diets go right and where they can also go very wrong. After 10 years of being a staunch conventional higher-carb, lower-fat vegan, yet still battling ongoing health problems, I recognized that this diet was not ideal for me, and I knew something had to change.


Make Your Life a Cleanse



Get FREE access to these + giveaways, recipes, & discount codes in personal emails from Dr. Will Cole.

I was not a “junk-food vegan.” I ate what most would consider an extremely healthy diet, consisting more or less of what I often see many vegans eating - vegetables and fruit, sure, but also quite a lot of sprouted grains, legumes, and other forms of carbs.

I wasn’t eating very much fat, and the result was that I was overloading on foods that raised my blood sugar, perpetuated my inflammation, and contributed to my digestive distress. There were plenty of things I liked about eating this way, but I could not deny that I did not feel healthy or at my best.

It was out of this experience that my book Ketotarian was born. By focusing on the ketogenic principle of a high-fat, moderate-protein, and low-carb ratio of nutrients, but getting those mostly through plant-based sources, I was able to transition my body from being a sugar burner to a fat burner while also avoiding the often-inflammatory effects of dairy and conventionally processed meats. I also shifted what plant-based foods I was eating, away from grains and legumes and towards healthy plant-based fats such as avocados and coconuts, protein from nuts and seeds, and of course, plenty of nutrient-rich vegetables. 

You probably have questions. One common criticism of vegan diets in particular is that they are protein-deficient. Is it really possible to get enough protein on a completely plant-based diet? In reality, you actually need less protein than most people think. In fact, in order to manage your blood sugar, it is essential to not overdo it on protein. Your body is incredibly smart, and when you starve it of glucose, it uses the process of gluconeogenesis to turn your protein intake into glucose for energy. Essentially, on a high protein diet, you are still using sugar for energy.

When you limit your protein, however, and increase your intake of healthy fats, your body doesn’t have much in the way of resources to manufacture more glucose, so it switches to using fat for fuel instead. This is what ketosis is all about. To get into this state, you should aim for around 0.5 to 1 gram of protein per pound of lean body weight - the amount of weight on your body that isn’t fat - per day.

But there is another consideration: Not all protein is created equally. The main issue when it comes to protein is about the specific kind more than the quantity. When you eat protein, it is broken down by your body into amino acids. Your body needs amino acids to function optimally. There are a total of 20 amino acids that your body needs; however, only nine are considered essential, and you must get them from your food:

  1. Valine: This branched-chain amino acid is responsible for energy production and muscle growth. (1)
  2. Threonine: This one plays a role in fat metabolism as well as helping to create collagen structure for skin and connective tissue health. (2)
  3. Tryptophan: As a precursor to your neurotransmitter serotonin, tryptophan helps regulate your sleep and mood. (3)
  4. Methionine: This amino acid is essential for tissue growth. (4)
  5. Isoleucine: Another branched-chain amino acid found in muscle tissue, isoleucine helps regenerate muscle tissue. (5)
  6. Lysine: This one plays roles in both energy production and protein synthesis. (6)
  7. Histidine: This amino acid produces histamine, which is a compound involved in immune responses. (7)
  8. Phenylalanine: This is a precursor to your neurotransmitters dopamine, epinephrine, norepinephrine, and tyrosine. (8)
  9. Leucine: Another branched-chain amino acid, leucine is involved with muscle health and protein synthesis. (9)

Foods containing all nine essential amino acids are considered complete proteins and are found most abundantly in meat, dairy, eggs, and seafood - all of which are not options for vegans.

But that doesn’t mean animal products are required. The truth is, we really can get all of the amino acids we need from plants alone. Some of my favorite lesser-known plant-based sources of complete protein include:

  • Hempeh (tempeh made from hemp seeds): 22 grams protein per 4 ounces hempeh
  • Natto (organic non-GMO): 31 grams protein per 1 cup natto
  • Tempeh (organic non-GMO): 31 grams protein per 1 cup tempeh
  • Hemp protein powder: 12 grams protein per 4 tablespoons powder
  • Hemp hearts/seeds: 40 grams protein per 1 cup hemp
  • Nutritional yeast: 5 grams protein per 1 tablespoon yeast
  • Sacha inchi seed protein powder: 24 grams protein per 4 tablespoons powder
  • Spirulina: 4 grams protein per 1 tablespoon spirulina

These plant-based protein sources not only provide an excellent amount of protein per serving, but they are also easy to incorporate into your daily meals as an addition to smoothies, on top of salads or other dishes, or alone as a snack (for plant-based protein options, check out my article on the subject). 

You may remember that old concept of “protein combining” or pairing. The idea was that because complete proteins are not always found in plant sources, each meal had to include all essential amino acids in some combination. Now we know that this isn’t necessary. We can get all our amino acids throughout the day, at various meals. When we chew, swallow, and digest our meals, our stomach doesn’t divide our breakfast, lunch, and dinner. All the meals for the day are being digested, and the nutrients absorbed and utilized. Because of this, all we need to do is focus on getting all the essential amino acids on a regular basis - not necessarily at every meal. Even though most plant foods don’t contain all nine essential amino acids, they are all represented in plant foods, so eating a wide variety of veggies along with some of the above complete protein sources can get you there. You’ll also get many other vital nutrients your body needs to function optimally.

Ultimately, the amount of protein a person needs varies for each individual and depends on many things; however, it’s important to remember not to overdo it. By focusing on cleaner sources of complete protein and a variety of other plant-based sources instead, you’ll not only be getting in the nutrients your body needs, you’ll be providing it with a balanced, healthier nutrition profile as well - without aggravating your blood sugar or compromising your efforts to remain in a fat-burning state.

As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe. 


Start Your Health Journey Today



  1. National Center for Biotechnology Information. PubChem Database. Valine, CID=6287, (accessed on July 2, 2020)
  2. National Center for Biotechnology Information. PubChem Database. L-Threonine, CID=6288, (accessed on July 2, 2020)
  3. National Center for Biotechnology Information. PubChem Database. Tryptophan, CID=6305, (accessed on July 2, 2020)
  4. National Center for Biotechnology Information. PubChem Database. Methionine, CID=6137, (accessed on July 2, 2020)
  5. National Center for Biotechnology Information. PubChem Database. l-Isoleucine, CID=6306, (accessed on July 2, 2020)
  6. National Center for Biotechnology Information. PubChem Database. Lysine, CID=5962, (accessed on July 2, 2020)
  7. National Center for Biotechnology Information. PubChem Database. Histidine, CID=6274, (accessed on July 2, 2020)
  8. National Center for Biotechnology Information. PubChem Database. Phenylalanine, CID=6140, (accessed on July 2, 2020)
  9. National Center for Biotechnology Information. PubChem Database. Leucine, CID=6106, (accessed on July 2, 2020)

View More At Our Store

Purchase personally curated supplements
and Dr. Will Cole’s books!

Shop Dr. Will Cole

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

Our content may include products that have been independently chosen and recommended by Dr. Will Cole and our editors. If you purchase something mentioned in this article, we may earn a small commission.



Evidence-based reviewed article

Dr. Will Cole, DNM, IFMCP, DC is a leading functional medicine expert who consults people around the globe, starting one of the first functional medicine telehealth centers in the world. Named one of the top 50 functional and integrative doctors in the nation, Dr. Will Cole provides a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. He is the host of the popular The Art Of Being Well podcast and the New York Times bestselling author of Intuitive Fasting, Ketotarian, The Inflammation Spectrum and the brand new book Gut Feelings: Healing the Shame-Fueled Relationship Between What You Eat and How You Feel.

Gut Feelings Dr. Will Cole 6

Gut Feelings

Healing The Shame-Fueled Relationship
Between What You Eat And How You Feel