Nutrition is innerestin'.
It's one of those fields where you hear contradicting data practically on a weekly basis. In many cases, nutritional information comes full circle, leading physicians (sometimes reluctantly) to do a complete 180 on their dietary recommendations—assuming they provide any recommendations at all, which I hate to say is pretty unlikely (research shows the typical doctor receives 25 hours or LESS of nutrition educational during their entire four years of medical school).
A prime example of this oops-we-were-wrong-about-that nutrition info is dietary fat. Long bastardized by the government and mass media, dietary fat is now largely accepted as an essential component to a healthy diet.
To pull on a similar thread, I see the same sort of thing happening with protein. After all, there's no question that protein is essential for your health. But my team and I field a lot of concerns regarding this macronutrient, with no small thanks to the conflicting information we hear about in the news: Isn't too much protein bad for you? How much do I actually need? Which protein sources are best?
In this post, we're going to get into the meat of the issue (no pun intended) and try to answer these questions using the best available information. My hope is that you'll see why protein is such an essential part of any healthy diet, and why you may in fact not be getting enough to support your lifestyle (hint: official dietary reference intakes may leave you lacking).
Protein Power: What This Little Macronutrient Does For Your Body
Protein is made up of at least 20 different "building block" molecules known as amino acids. When we consume protein, it gets broken down into these smaller units, which are then shuttled throughout the body where they participate in dozens of physiological functions, including (but not limited to):
- Building and repairing cells, tissues, and organs
- Synthesizing important compounds like enzymes and hormones
- Regulating gene expression
- Assisting in key metabolic processes
Basically, when protein gets into your body, it rolls up its sleeves and says, "I got you, boo." You need it to live, and without enough of it your physical and even mental health can suffer.
So, How Much (And What Kind of) Protein Do I Need?
Here are two simple concepts to keep in mind regarding protein intake:
- We ALL need protein. You may need more or less protein than others, depending on factors including your health, health goals, and lifestyle.
- Not all protein sources (nor its constituent amino acids) are created equal, so you need variety of sources to cover your bases.
Let's tackle these points one by one, starting with number 2.
Protein Source
Your body can create some but not all the amino acids it needs for optimal health. I'm thinking of nine in particular: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These are "essential" amino acids: they must be sourced from your diet because your body can't synthesize them on its own.
As it turns out, animal protein—including meat, fish, seafood, eggs, fowl, bone broth, and offal (organ meat)—are considered complete sources. They give you all the amino acids your body needs (including the nine essential ones) for surviving and thriving.
Meanwhile, plant protein is considered incomplete—it's missing many of the essential amino acids. This is not to say skip them altogether. To the extent that plant protein sources like beans, lentils, and chickpeas contain other beneficial compounds including fiber, minerals, and vitamins, it's still a good idea to add them into your diet. Rotating in plant protein can also keep your meals interesting and ease the strain on your wallet, too.
Based on the evidence, it's fair to say that consuming a variety of animal and plant protein (ideally high quality and ethically sourced) is optimal for ensuring your body gets what it needs. (As you can imagine, I do caution against certain types of plant protein, including soy and gluten-containing grains, because of their deleterious effects on health, but that's a bit beyond the scope of this article, so I'll defer that discussion for now.)
Protein Intake
According to the government, the official dietary reference intake (RDI) for the typical adult is about 0.8 grams per kilogram of body weight, or in our funny American units about .36 gram per pound.
If you're counting, that's about 54 grams of protein for a typical 150 pound person.
Here's the big BUT:
This DRI is set for an average sedentary person. It may be enough to stave off deficiencies, but in all likelihood it's not enough for a lot of us, especially if we're active.
In fact, many people need a LOT more than this, including anyone who:
- Is trying to slim down and lose excess body fat.
- Is trying to manage their blood sugar and metabolism more effectively.
- Is elderly or chronically ill.
- Is under chronic stress.
- Trains hard and/or has a physically demanding job.
For these reasons, I often recommend that my clients consume upwards of 20-35% of their daily calories from protein, or as much as 1.2+ grams of protein per kilogram of bodyweight, depending on their needs. By all accounts, this may be considered a "high" protein diet.
But Isn't High Protein Bad? Busting the Myths Surrounding this Macronutrient
Many people get squirrely about increasing their protein intake after seeing headlines that say eating meat gives you cancer or that high protein diets cause kidney damage. I get it. You want to do what's right, right?
To be brief, let me start by saying that a high protein diet does NOT cause kidney damage in individuals with normal kidney function. This is well-supported by the literature. Whereas low-protein diets can certainly be therapeutic for people who already have kidney disease, there's just no evidence to suggest that consuming high levels of protein causes kidney disease in otherwise healthy people.
Indeed, studies actually show that a high protein diet can protect against high blood pressure and diabetes—both of which are risk factors for kidney disease.
As for studies that suggest eating meat increases cancer risk, a closer look at the data reveals important caveats. For one thing, a lot of these studies are observational, which make it hard to understand causation and are often rife with bias and faulty self-reporting. Additionally, it's not as if the evidence paints protein in a purely dark light—data shows, for instance, that high protein intake is protective against cancer-related mortality for people over the age of 65.
Here's another key point to tease out: animal protein like meat and eggs are abundant in an amino acid called methionine. Methionine DOES happen to be associated with increased levels of insulin-like growth factor-1 (IGF-1), which has been linked with cancer and shortened lifespan in animal models. To this end, it makes sense at face value that consuming a lot of meat and eggs may increase cancer risk.
BUT—and this is an important but—in studies where subjects consumed adequate levels of another amino acid called glycine, the potentially harmful impact of high methionine were effectively mitigated.
Glycine, which can be synthesized by our body but likely not enough for optimal function, is rich in connective tissues and organ meats such as liver, gelatin, and bone broth.
In other words, the research circles back to the importance of getting a variety of protein in your diet! Consuming animal protein from connective tissues and organs in addition to meat and certain plant proteins will help you get the right balance of amino acids and optimize your health and longevity.
Conclusion
You need enough protein to support lean body weight, basic physiological functions, and physical activity—because science.
You need to consume a variety of protein sources to ensure you're getting the right balance of amino acids, and should not skimp on "extras" like bone broth and collagen supplements.
As for determining exactly how much protein YOU need, this requires some simple experimentation, which, if you're otherwise healthy, you should be able to do freely.
Ask yourself: Am I sleeping well? Am I recovering from workouts well? Do I have high levels of stress? Do I train hard? Am I on my feet all day? Am I trying to lose body fat or control my diabetes? Am I older than 65? Answering these questions can help you determine where on the spectrum of protein intake you should fall—that is, closer to 20% of your daily caloric intake or upwards of 30 to 35%.
And while I always advise anyone with chronic health problems to consult with their doctor before making any changes to their lifestyle and/or diet (especially if you have kidney problems, for the purposes of this discussion), rest assured that if you're otherwise healthy, upping your protein intake will not hurt you, and if anything will likely help you look, function, and feel better than ever.
Team, what's your protein perspective? Let me know about it in the comments.
Sources:
https://chriskresser.com/5-reasons-you-may-need-more-protein-even-on-a-paleo-diet/
https://www.ncbi.nlm.nih.gov/pubmed/20093739
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2780010/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430660/
https://www.sciencedirect.com/science/article/pii/S155041311400062X
https://chriskresser.com/do-high-protein-diets-cause-kidney-disease-and-cancer/
https://www.healthline.com/nutrition/how-much-protein-per-day
https://www.ncbi.nlm.nih.gov/books/NBK234922/
https://www.marksdailyapple.com/why-the-variety-of-your-protein-sources-matters/
https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx