The Most Nutritious Sources of Proteins (According To Science)

Written By: Paul Jenkins MSc, Supplement Expert, Nutritionist & Sports Coach

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Whether we hear about it in commercials, health facts, cooking shows, or the news, there’s just no escaping protein in the media. Given the crucial part it plays in the proper functioning of the human body – after all, if there is one molecule that best embodies the trite adage of “you are what you eat,” it’s protein – advocating for the importance of this macro-nutrient has never been more justified. What isn’t justified is using protein solely as a marketing tool. 

In this article, I’d like to give you an overview of what protein does for your body and what determines the quality of protein, but also to illustrate the absolute best sources of protein from food or supplements. As I give this advice, which is not medical, although informed by a relevant career, education, and experience, my foremost concern is promoting health and healthy behaviors. I also live by these guidelines and, where necessary, recommend them to my clients.

Why We Can’t Live Without Protein

Let’s get our periodic table geek on. Most people know protein as the building block for the organs and tissue in our bodies. It’s everywhere, from your hair and skin to your bones and muscles. It powers our metabolism and growth in a variety of ways. For example, proteins carry oxygen to cells (which keeps them alive) and it enables the process of making new cells by “reading” our DNA and then, well… 3-D printing them, in a manner of speaking [1].

In human nutrition, protein is made from more than 20 amino acids (AAs). The problem with these is that we don’t store them in the same way we do fat, although our muscle tissue does stock some limited reserves and will resort to using them in times of crisis – such as starvation, injury, or when we’re fighting disease. Wait, disease? That’s right. Aside from its role as a structural component and messenger, protein also plays a vital part in fighting diseases. 

The very antibodies that protect us from viruses, harmful bacteria, other pathogens, and toxins are, essentially, protein [2]. They’re incredibly specific, as the antibody-producing cell tailor-makes a precise molecule in order to get rid of a pathogen.

Since storage is not a reliable option, the human body constantly makes AAs from scratch, i.e. by breaking down the food we eat or by playing with the AAs that are currently available and transforming them into what it needs. Out of all the AAs, 9 are essential. They’re called this way because our metabolism cannot modify others to get them. As such, we must procure the 9 essential AAs from food [3].

 “Packaging” Is Essential

Scientists have begun to pay an increasing amount of attention to the packaging of protein, which basically refers to everything that our digestive system has to go through to get to the protein itself. Depending on where you get it from, the latter can either bring you good things, such as fiber and antioxidants, or bad ones, such as sodium and saturated fat. Today, most people living in developing and/or developed countries are at very low risk of being protein deficient.

However, there is a literal mountain of evidence pointing to the role that processed and red meat have in what concerns heart diseases, diabetes, cancer, and premature death [4]. The difference? Plant-based protein doesn’t have meat’s unhealthy packaging. Instead, it comes wrapped in dietary fiber, vitamins, minerals, and phytonutrients which increase our quality and span of life, while lowering our odds of developing the above-mentioned diseases and more [5]. Most of the animal protein we ingest was initially made from plants since they’re herbivores themselves. In a manner of speaking, animal protein is second-hand. 

Don’t plants have inferior quality protein? This is yet another misconception largely attributed to marketing, rather than evidence-based nutrition. Each and every plant you eat has all the essential amino acids [6]. True, some plant foods are lower in certain amino-acids than others, but so long as you eat your fill from more than once source (which we’re naturally predisposed to do), there’s nothing to worry about [7]. 

Tips to Help You Get Enough Protein for Maintenance and Building Muscle

So, what are some reliable protein sources that won’t negatively impact your health? Here are some good sources of protein that will keep you strong, as well as more information related to their recommended intake. 

The recommended daily allowance (RDA) is about 0.8 grams per kilogram of body weight, while bodybuilders and strength athletes fare better with 1.6 to 2.2 grams/kg [8] and endurance athletes are somewhere in between the two. Physically active people need more protein because they regularly engage in strenuous activities that lead to micro-tears in the muscle tissue. To keep them going, their lean mass requires more AAs to repair itself. 

That’s 56 grams of protein for a regular person weighing in at 70 kg for maintenance and an upper limit of about 120 grams for strength training. Any more than this doesn’t necessarily have any beneficial impact on muscle gain. 

Supplemental Sources of Protein:

My advice is to go for isolated protein sources that contain above 80% protein by weight. Although such a ratio of protein to carbohydrates and fat is not usually possible in the case of hemp or pea. 

1. Whey Protein Powder. This is readily absorbed by the body, contains all essential amino acids, helps support immune function, and is a staple of the bodybuilding and fitness industry. 
2. Soy Protein Powder. If you’re not allergic, you can reap the benefit of not triggering the inflammatory response associated with proteins found in dairy protein powders. However, soy is not as effective as whey in triggering muscle protein synthesis (MPS) [9].
3. Hemp Protein Powder. Much like soy, hemp is considered a complete plant-based protein. It’s incredibly easy to digest and a good source of fiber, as well as healthy fats, but it has a distinct, earthy taste. 
4. Pea Protein Powder. A balanced profile of AAs, although slightly lacking in methionine, which you can find in squash, rye, broccoli, brazil nuts, spinach, soy and more.

Whole Food Sources of Protein:

My advice is to combine these categories to your liking; you should also find that you reach satiety sooner than you would when consuming a lesser amount of protein. If you also switch from white flours, grains, and pasta to whole-wheat ones, then you needn’t even worry about the carbohydrate content affecting your fat mass, since the glycemic impact of whole-food carbs is quite small and balanced out by their natural fiber content.

1.Pulses, Legumes, and Whole Grains. 

• Beans. Kidney, black, any kind, really, as they have an average of 20g of protein for 100g of product. They go really well with brown rice.
• Hummus. Incidentally made from chickpeas, another popular bean. Goes amazingly with carrots as a snack between meals.
• Lentils (10g of protein for 100g). An easy addition to plain rice and a perfect base for cream soups.
• Soy (36g for 100g). Textured soy protein has a whopping 50 grams of protein for 100 grams of product. And no, you don’t need to worry about any of the so-called studies saying it acts as estrogen in our bodies [10]. Soy actually behaves as a phytoestrogen and serious trials indicate it has no impact on actual testosterone or estrogen levels. Edamame, tofu, and tempeh are also great sources of complete soy protein.

2.Nuts and Seeds.

• Pumpkin Seeds (30 grams of protein per 100 grams).
• Sunflower Seeds (21 grams per 100).
• Nuts (20 grams per 100).
• Almonds (21 grams per 100).

I’d be very careful about the salt content of the packaged nuts and seeds you buy. The best kinds are raw (and/or toasted, but with no salt), as they will contribute to your overall satiety and help your body re-stock on healthy fats. In terms of cost-per-gram, nuts and seeds are quite an expensive source, so you should probably limit them to snacks. Even though this article is written with respect to protein, I find it hard not to mention the essential fats that nuts and seeds can provide you with. Fats too are incorporated into your structure, with nuts and seeds you get the double whammy of essential amino acids (EAAs) and essential fatty acids.

3.Fish and Poultry. 

If you find it difficult to consume all of your protein from plant-based foods, fish and poultry are great alternative options to red meat. In fact, many top-level athletes rely on seafood and fish as their primary protein sources. Most of them are doing it for health reasons since large amounts of red and processed meat is associated with an increased low-grade inflammatory response that prevents speedy muscle recovery. For example, on average seabass has 23 grams of protein per 100 grams, haddock has round 21 grams and salmon around 20-21 grams. 

Wild-caught seafood is more advisable than farmed. On average, the former will have a better diet, which leads to improved nutritional value and taste. In addition, wild fish is less likely to show signs of contaminants. By comparison, 100 grams of lean red meat (beef) has 23 grams of protein. 

Final thoughts

As a nutritionist, coach, and chemist, this is my opinion in terms of the best sources of protein that keep us healthy and strong. So far, there is an abundance of medical and anthropological research that supports it. The future might yet bring another nutritional revolution, but right now, this is the best we have.