Stop for a minute and consider: Your body can store carbohydrate (as glycogen). Most of us know – all too well, unfortunately – that it can store fat. But you cannot store protein, making this macronutrient – or more specifically, the nine essential amino acids that make up protein – absolutely necessary.
Even the word’s etymology – “protein” comes from the Greek word meaning primary – suggests its utmost importance.
You might think asking how much protein you need daily would provide an easy answer. It doesn’t. For such a seemingly simple macronutrient, protein can get really complicated and contentious.
“Human protein and amino acid nutrition encompasses a wide, complex, frequently misunderstood, and often contentious area of clinical research and practice,” says L. John Hoffer in a comprehensive review about dietary protein. (1)
As you’ll see, he isn’t kidding.
Think back to high school biochemistry class. You might recall the many roles protein plays in your body. Protein is the major structural component of muscle and other tissues. Your body uses protein to produce hormones, enzymes, and hemoglobin. (2)
“Protein is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue,” says the Harvard School of Public Health. “It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. At least 10,000 different proteins make you what you are and keep you that way.” (3)
To utilize protein for those and other roles – stop and ponder that last sentence: at least 10,000 proteins – your body must break it down into its simplest form, called amino acids. Of the 20 amino acids, your body cannot synthesize nine, deeming these amino acids “essential.” (4)
Put another way, while your body can synthesize non-essential amino acids from other food sources including carbohydrate, you must get those nine amino acids from external sources; namely, supplements or more likely, food.
From that perspective, how much protein – or how many grams of protein – your body needs to optimize and maintain all these functions becomes a massively loaded question.
A few caveats before we get started: Dietary protein encompasses a wide range of topics, including the functions of specific amino acids (such as lysine or branched chain amino acids) and evaluating the best protein powder.
Likewise, people respond to specific proteins differently. Cow’s milk might provide a superior source of protein compared with plant foods, but for many people it can create reactions that make it a terrible protein source.
These and other important intricacies about protein surpass this article’s scope. Here, we’ll look at what optimal protein intake looks like and address two specific demographics – athletes and vegans/vegetarians – who often have different protein requirements.
How Much Protein Do I Need? The Experts (Attempt to) Respond
While many experts and organizations agree about the importance of dietary protein, determining how much you need isn’t nearly so clear-cut.
The Recommended Daily Allowance (RDA) for protein is 46 grams per day for women over 19 and 56 grams per day for men over 19. (5)
The RDA, by the way, is the average daily dietary nutrient intake level sufficient to meet nutrient requirements for 97 – 98 percent of healthy individuals in a particular life stage and gender group. (6) Worth noting: The RDA for protein hasn’t changed in over 70 years. (7)
Put that into perspective: According to the RDA, a woman needs the protein in about six ounces of a chicken breast daily. For a guy, that becomes about eight ounces. You’re correct if you think that sounds low.
“What most people don’t realize is that this is the minimum necessary to prevent protein deficiency, not the optimal amount needed for robust health or building muscle — one of the most important organs in your body,” says Mark Hyman, MD, about the RDAs in Food: What the Heck Should I Eat? (Worth mentioning: Hyman wrote the forward to my book Align Your Health.)
The RDA is one type of Dietary Reference Intakes (DRIs). The DRIs recommend adults get a minimum of 0.8 grams per kilogram (kg) of body weight of protein. According to those numbers, a 200-pound sedentary man would need about 73 grams of protein daily. (You can grab a handy protein calculator to determine your needs here.)
Even then, the DRIs don’t make things much clearer. They argue adults should consume 10 – 35 percent of calories from protein daily, something called the Acceptable Macronutrient Distribution Range (AMDR), which was developed to put dietary recommendations in the context of a complete diet. If you do the math, you’ll note the lowest level of protein intake recommended in the AMDR is higher than that of the RDA. (7)
That’s quite a wide range (10 – 35 percent) to determine exactly how much protein you need, and yes, those numbers can get confusing. Experts aren’t much more help. Some argue we get too much protein. Others claim we need more.
“One of the great myths of modern diet is we all need more protein, but in this country almost all of us get more than we need,” say Mark Bittman (author of How to Cook Everything Vegetarian) and David L. Katz, MD, in a recent New York Magazine interview entitled “The Last Conversation You’ll Ever Need to Have About Eating Right.”
“We need less protein than most of us get [and] getting enough protein is easy,” they argue, “which is why there is virtually no such thing as protein deficiency in the USA outside of hospital wards (where it is an effect, not a cause, of serious illness).” (8)
Not everyone agrees that we’re eating too much protein.
“We think that most people aren’t consuming nearly enough clean protein and that the standard recommendations are too conservative,” write Jonny Bowden, PhD, and Steven Masley, MD, in Smart Fat.
Evaluating the RDA recommendations – which you’ll remember, are about 46 – 56 grams of protein daily for sedentary adults – don’t account for certain variables like being under- or overweight that might impact protein intake, Bowden and Masley argue.
“Is she pregnant? Is she an athlete? Is she menopausal? How old is she?” they ask about these RDA’s paltry protein recommendations. “All of these factors affect her protein intake, but except for basic human survival, 47 grams wouldn’t be adequate in any scenario.”
In other words, everyone is different and has different needs. Putting a one-size-fits-all label on protein (or anything) doesn’t help determine optimal amounts for you, with your specific conditions, your age, your level of activity a particular day, your sleep levels, and so much more.
Research about dietary protein and health conditions isn’t any clearer. Studies regarding protein intake and chronic disease risk – including Type 2 diabetes, cancer, and cardiovascular disease – are all over the map. Evaluating all the research would likely leave even the science-savviest reader confused. (9)
One thing experts are a little more certain about: Dietary protein might help you lose weight and maintain that weight loss. That’s because compared with dietary fat or carbohydrates, protein is typically more satiating. In other words, it makes and keeps you full for fewer calories. Research also shows protein can increase thermogenesis (fat burning) and help maintain or build muscle. (10)
From all that evidence, you would rightly feel confused wondering whether you eat too little or too much protein.
In one sense, most of us are eating enough protein. Bittman and Katz correctly argue overt protein deficiencies rarely occur in most first-world countries. Although rare here, protein undernutrition in third-world countries is tragic and can result in stunting, anemia, physical weakness, edema, vascular dysfunction, and impaired immunity. (11)
Typically, these protein deficiencies occur along with nutrient and overall caloric deficiencies from insufficient food intake. (4) Consider the massive amounts of food most people eat in Western societies daily. Now consider the RDAs for protein (46 to 56 grams daily), which are the basic amounts most adults need to survive. Most Americans aren’t going to display overt protein deficiencies, right?
But preventing deficiencies and thriving are two very different things. As critics like Bowden and Masley note, we don’t simply want to get by with “minimal-wage nutrition” protein intake. We want to be healthy, lean, and full of energy. And to do that, we need optimal amounts of protein.
Researchers find the average American consumes around 16 percent of total calories from both plant and animal protein, and they might need much more.
At least that was the consensus among over 40 nutrition scientists, who met in Washington, D.C., for “Protein Summit 2.0” in 2015 – the first one happened in 2007 – that was sponsored by beef, egg, and other animal-based food industry groups. (Read into that what you will.)
“The Protein Summit reports in [the American Journal of Clinical Nutrition] argue that 16% is anything but excessive,” writes Daniel Pendick in Harvard Men’s Health Watch. “In fact, the reports suggest that Americans may eat too little protein, not too much. The potential benefits of higher protein intake, these researchers argue, include preserving muscle strength despite aging and maintaining a lean, fat-burning physique.” (5)
Can You Eat Too Much Protein?
You need – and want – optimal amounts of protein. But exactly how much exactly should we eat, and what are the consequences of over-eating protein?
If you remember the zenith of the low-carb Atkins Diet back in the early 2000s, some critics bemoaned all that dietary protein could set the stage for kidney or other problems. Interestingly, while these low-carb diets earned a reputation as being high-protein diets, (12) they – along with ketogenic diets, which have become popular in 2018 – are high in dietary fat, moderate in protein, and very low in carbohydrate. (13)
Regardless, these critics raised a very good point: How much protein is too much protein?
Researchers believe consuming two grams per kg body weight daily is safe for healthy adults. The tolerable upper limit is 3.5 g per kg body weight per day for well-adapted subjects. (11) For a 200-pound man, that would be around 300 grams of protein daily.
What happens if you exceed those limits? From a practical perspective, you might over-consume calories, and you’re more likely to gain weight and all its health-robbing repercussions.
If you’re doing a ketogenic diet, too much protein could theoretically knock you out of ketosis, though how much would likely differ among individuals.
“Proteins are broken down into amino acids and absorbed, and excess amino acids may also be turned into glucose,” says Jason Fung, MD, in The Complete Guide to Fasting. “Protein does not raise blood glucose, but it can raise insulin levels. The effect is variable, and it surprises many people to learn that some proteins can stimulate insulin as much as some carbohydrate-containing foods.”
More worrisome, some researchers speculate chronic high protein intake (over two grams per kg body weight daily for adults) could theoretically create digestive, renal, and vascular abnormalities. (11)
Likewise, the American Heart Association suggests high-protein diets could adversely impact liver function (theoretically burdening your liver with higher protein intake). Yet researchers find no scientific evidence to support this argument. In fact, protein plays a role in liver health including tissue repair. (12)
Ditto for kidney disease: While a high-protein diet could create problems with people who have existing kidney dysfunction, little evidence shows high-protein intake is dangerous if you’re healthy. (14)
Can You Get Enough Protein as A Vegan or Vegetarian?
Bring up protein intake among vegans or vegetarians and you’re likely to ruffle some feathers. You might hear several arguments, including that most Americans over-consume protein and higher amounts aren’t as essential as some people might believe.
Even more hotly debated is the protein quality in plant foods. A complete protein provides all nine essential amino acids. Unfortunately, many plant foods are low or otherwise lacking in one of those amino acids.
“While plant alternatives to meat are increasing in popularity, there is no getting around the fact that meat is the single best source of protein (and also many vitamins and minerals),” Hyman says. He notes that of all plant protein sources, only quinoa, buckwheat, and soy contain all nine essential amino acids.
One way to remedy that problem – in other words, ensure you get all nine essential amino acids – is through protein combining or complementary proteins: Eating two or more plant foods that, combined, would create a complete protein.
However, many critics argue that theory has been debunked, and many organizations including the American Dietetic Association and Dietitians of Canada dismiss protein combining as unnecessary as long as vegans and vegetarians eat a varied diet. (16)
Even for vegetarians, who have more variety with eggs and dairy, getting sufficient protein can be challenging.
“If you rely on eggs, then you’d have to eat a whole lot of omelets,” says Hyman. “Fulfilling your protein requirements with non-meat foods requires enormous planning and effort, more than most people can manage.”
Then you have the problem with potential food sensitivities and allergies in soy, dairy, eggs, and other plant foods. Overeating these foods – soy is a biggie, especially the processed soy products positioned as health foods – could create problems like leaky gut in the bigger picture.
There’s also the impracticality of exclusively relying on plant foods for protein. A cup of broccoli contains about 2.6 grams of protein. (17) By contrast, a four-ounce chicken breast contains 31 grams of protein. (18) You’d need to eat nearly 12 cups of broccoli to get that amount.
Yes, certain plant foods are higher in protein, such as legumes. But according to Hyman, they present other problems including lectins and phytates that can block nutrients. He says beans can also promote overgrowth of bad bacteria in your gut, potentially creating gas and systemic inflammation.
Listen, you’ve got tons of reasons to eat broccoli – one of the most nutrient- and antioxidant-loaded foods on the planet – but protein shouldn’t be one of them. Broccoli is an incredibly great way to get nutrients and fiber but an inefficient way to get protein. Likewise, beans can make a perfectly fine side dish, but overeating them can create problems.
In all fairness to vegans and vegetarians, animal protein contains its own problems, especially when those foods come from factory-farmed animals not fed their natural diet. And overeating nearly any food can create problems. That’s why I believe — for most people — eating animal and plant protein foods becomes ideal.
Can you be a vegan or vegetarian and get optimal protein? Absolutely. But it also requires more work and remaining cognizant about particular issues with plant-based proteins including food sensitivities.
Protein and Athletes
Perhaps more than any other demographic, athletes seem obsessed with protein. Visit nearly any gym or health food stores and you’ll find hulking containers of protein powders and amino acid supplements. You’ll find bodybuilders un-self-consciously scarfing down chicken breasts post-workout.
That makes sense when you consider protein – or more specifically, amino acids – are the building blocks for muscle. From that perspective, most experts agree athletes need more protein than sedentary individuals. How much more depends on several factors including athletic intensity and age.
“Based on available research… protein requirements are higher in very active individuals and suggested that resistance athletes need 1.6–1.7 g protein/kg body weight while endurance athletes need approximately 1.2–1.4 g protein/kg, values that are about 150–200 percent of the current United States Recommended Dietary Allowances (RDA),” says Melvin Williams. (15)
The Recommended Dietary Allowance (RDA) for protein, which you’ll remember is 0.8 grams per kilogram (kg) of body weight for sedentary folks, increases for athletes according to their activity levels. More specifically:
- Minimal exercise – 1 gram (g) per kg
- Moderate exercise – 1.3 g per kg
- Intense exercise – 1.6 g per kg (11)
In other words, if you’re doing high-intensity interval training or lifting heavy, you’ll need about double the protein what a sedentary person requires. That still isn’t a lot.
Yes, you can be a vegan or vegetarian athlete, but you need to be more cognizant about protein intake.
“As you age, you need more and higher-quality protein to maintain muscle mass and health,” says Hyman. “Plant proteins contains low levels of leucine, the rate-limiting amino acid for maintaining and building muscle, whereas animal protein contains high levels of leucine.”
That doesn’t mean if you’re an athlete (vegan or otherwise), you need to become compulsive about protein. During intermittent fasting, Fung says you deplete glycogen stores after 24 – 36 hours. Your body subequently prefers burning fat rather than protein (muscle). In fact, Fung argues protein breakdown actually decreases during fasting.
“The normal protein breakdown of around seventy-five grams per day falls to fifteen to twenty grams per day during fasting,” he says. “Rather than burning muscle during fasting, we start conserving muscle. Much of the amino acids that are broken down during regular turnover of cells are reabsorbed into new proteins.”
7 Protein Takeaways
As you’re probably now aware, dietary protein can get complicated. Worth repeating: You can get by perfectly fine without carbohydrate and dietary fat (at least for a while), but you absolutely need protein, or at least the nine essential amino acids in protein. That’s one reason optimal protein amounts get hotly contested.
You’ve read a lot of numbers in this article. Here’s the thing: Most people don’t sit down and think, “I’m eating 30 grams of protein in this chicken breast.” Instead, they think, “I’m eating a chicken breast.” Unless you’re a fastidious nutrition-focused person, an athlete, or you just like numbers, you don’t see food in grams or calories or anything else. You see food.
“People don’t eat ingredients; they eat food, says Hyman. “And they often eat foods that contain dozens of different ingredients, many different types of fats, proteins, carbohydrates, vitamins, minerals, phytonutrients, and more.”
Ultimately, food is complicated, as it should be. And isolating a single nutrient – in this case, protein – helps us better understand food but doesn’t evaluate the entire picture.
That grass-fed steak isn’t just protein; it’s also healthy fat, vitamins and minerals, and essentially conditional nutrients like L-carnitine and coenzyme-Q10. A plate of black beans isn’t just protein. It also includes fiber and phytonutrients.
Everyone is different, and based on specific variables – how old you are, how active you are, whether you have chronic disease, and so on – you will need different amounts of protein. With that in mind, these seven principles can guide you to determining optimal amounts.
1. See how you feel.
Biochemical individuality is a fancy way of saying everyone’s different. If you’re concerned about protein intake, keep a food journal and track how much you eat daily. Play around with different amounts (within reasonable limits) and see if things get better or worse. Focus on things like mental clarity, energy levels, and sleep quality. Remember that 10 – 35 percent recommend protein range? That’s pretty broad, so see where you fall within that range.
2. Be aware certain conditions might require more protein.
Chronic stress, aging, certain illnesses, and intense athletic training are among the situations that often require more protein. That doesn’t mean you need to rush to your health food store and stock up on massive containers of protein powder to cover your protein bases. Working with a health care professional or qualified nutritionist can help tweak your intake so you get sufficient amounts under these conditions.
3. Center protein intake on animal foods (if you can) but don’t neglect plants.
Researchers in one review suggest high-quality proteins from – don’t shoot the messenger – animal products for optimal human growth, development, and health. (11)
“That doesn’t mean meat should be your only source of protein,” says Hyman. “You can get a portion of your daily protein from plants. But for most people, especially as we age and need more protein to maintain our muscle mass, animal protein is important.”
4. If you can’t, focus on protein-rich plant foods.
Quinoa, legumes, nuts, and seeds are all good plant protein sources. You should be able to get all your protein from food, though you might also consider a pea/rice combination or other vegan-based protein powder if you feel you aren’t getting sufficient protein from plant foods.
5. Eat mostly real food.
Stop worrying so much about macros and focus instead on nutrient-dense, whole, unprocessed foods. Fill your plate with quality animal protein (if you can) or protein-rich legumes and other plant foods (if you can’t) plus plenty of non-starchy vegetables and bam, you’ve got an easy way to meet your protein – and overall nutrient – quota without counting grams or anything else.
6. Space it out.
Some studies mentioned at the Protein Summit 2.0 find spacing out protein over your day rather than eating most of it during dinner is more effective. (5) This shouldn’t be a problem for most people, but getting enough protein at every meal and snack becomes a great way to sustain energy levels and focus while staying satiated and reducing cravings.
7. When in doubt, shoot for 20 – 30 per meal.
According to Hyman, the average adult needs about 60 – 90 grams of protein daily, and even more if you’re active. Make that simple: Aim for about 20 – 30 grams at each meal, preferably from animal and plant sources. That’s not a lot of protein: About a three-egg omelet, about four ounces of grass-fed steak or wild-caught salmon, or about 1.5 cups of lentils. If you’re an athlete or otherwise active, have a protein-rich snack. Easy and done.
With protein – as with food in general – quality and quantity matter. Eating too much food with healthy protein isn’t smart, but neither is eating protein from processed foods or foods that can create potential food sensitivities. Find your balance with the right amount of protein that works for you, and be aware that amount might change on days where, say, you’re more physically active.