If you’ll permit me a rant—I promise to make it fact-filled and interesting—I am sick of the articles that seem to pop up every few months claiming that we are all eating “too much” protein. They convey an inaccurate picture of how the body uses protein, and they demonize perfectly healthy meals that happen to be high in protein. It’s time to set the record straight.
How can these articles be so wrong? I think the authors are usually well-meaning, but their facts don’t support the conclusion. They tend to bolster their argument with statements that are true, like the fact that the RDA of protein is set at 0.36 grams per pound of body weight, that protein-boosted foods are trendy, and that it is possible to get plenty of protein while eating a vegan diet. But the framing and the conclusions don’t follow, because eating more than the minimum doesn’t mean that you’re getting “too much” protein.
What foods contain protein?
As a refresher, protein is one of the three calorie-containing macronutrients (fats, carbs, protein) that make up our diets. Proteins are made of amino acids, and they are required for the growth, repair, and functioning of our body.
We can get protein from a variety of sources. Meats are particularly protein-dense; a chicken breast contains about 35 grams of protein. Other animal products, like milk and eggs, are also rich in protein. Plant-based foods tend to have less protein, but it’s not hard to meet or exceed protein requirements even on a vegan diet. Beans, grains, and soy products like tofu contain significant amounts of protein, for example.
If you’d like a cheat sheet on how much protein you’re supposed to eat based on your activity level, you can find one here. And that’s a good place to start dissecting this “too much protein” myth, because before we can declare an amount of protein to be “too much,” we need to understand how much is “enough.”
The RDA is meant to be considered a minimum
The government communicates targets for different nutrients to encourage us all to eat a healthy, balanced diet. These targets are the basis for the “% daily value” labels on the back of packaged foods, and for the nutrient makeup of school lunches. The RDA, or recommended daily allowance, is defined as “the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a group.”
So how is that “nutrient requirement” determined? For protein, it is based on nitrogen balance. Humans break down proteins, excreting nitrogen, as part of the body’s daily function. If you eat enough protein (which contains nitrogen), the amount of nitrogen you excrete will be the same as, or more than, the amount you eat. In other words, if you aren’t breaking your own body proteins down (in excess of what you eat), then whatever you’re eating must be, in some sense, enough.
In this way of thinking, the RDA is the minimum to stay healthy. More is fine; less would mean that you may not be getting enough. For some nutrients, there is also an UL, or upper limit, telling you that more than a certain amount is too much. Upper limits are calculated for vitamins and minerals; there is no upper limit defined for protein.
Therefore, there is no official definition for “too much” protein. If somebody eats more than the RDA, they’re not eating too much; they’re just eating more than the minimum. You’re supposed to eat more than the minimum.
How much is the RDA for protein, and how much is the average American actually eating?
The RDA for protein is set at 46 grams per day for a 125-pound woman, and at 56 grams per day for a 154-pound man. That’s based on an RDA of 0.8 grams of protein per kilogram bodyweight, which works out to 0.36 grams per pound. So a 200-pound person would need 72 grams of protein per day.
This USDA report found that most adult men average between roughly 90 to 100 grams of protein per day, although men aged 70 and up only get about 80 grams of protein per day. Women tend to average around 70 grams per day, with those aged 70 and up averaging 62 grams.
Above the RDA? Yes. Too much? I don’t see any way of arguing that. And before you say that we’re getting almost double the recommendation, let’s check the math. Those RDA numbers are for 125- and 154-pound people. On the other hand, the averages for what we eat are based on actual people, not ideals. The average American man is 200 pounds, and the average American woman is 171 pounds. That puts their RDAs at 72 and 62 grams per day, respectively. Relative to those numbers, the average woman is just barely beating the minimum; the average man is 20-25 grams over.
Again, there’s no need to stick to the minimum; going 25 grams over is fine. It’s probably better to go over than to just scrape by, and many of us arguably don’t get enough. Let me explain.
Many older adults don’t get enough protein
Let’s start with older adults. Not only does protein intake tend to decrease with age, older adults are vulnerable to issues that stem from a loss of muscle mass. People tend to lose 3-5% of their muscle mass per year starting at age 30, but strength training and protein intake can support maintaining our muscle, and thus likely prevent or reduce that decline.
The Dietary Guidelines include a note that “About 50 percent of women and 30 percent of men 71 and older fall short of protein foods recommendations.” Meanwhile, a study found that older adults who don’t meet the recommendations are “more likely to be limited when stooping, crouching, or kneeling, standing or sitting for long periods, walking up 10 steps, preparing meals, and walking for a quarter mile.”
So even if it’s true that the average adult gets more protein than recommended, there are clearly a lot of elderly folks who don’t. These are the same people who have more issues functioning in everyday life. This may be a chicken-and-egg situation—was the functional decline a cause or an effect of the change in their diet?—but this sure does not seem to be a group of people who should be eating less protein.
You need more than the default RDA if you’re pregnant or lactating
There’s another large group of people who benefit from more, not less, protein: people who are pregnant or lactating. Instead of 0.36 grams of protein per pound of bodyweight (62 grams for a 171-pound person), the RDA for people who are pregnant or lactating is 0.5 grams/pound (so, 86 grams of protein per day).
When you’re pregnant, you also have higher caloric needs, so the increased total amount of food makes it easier to get the higher protein amount. Still, it makes more sense to spend your energy on making sure you’re getting enough protein, rather than worrying about getting too much.
Higher-protein diets support healthy exercise and muscle mass
You knew we heading in this direction (I say between reps of barbell squats, wiping protein shake off my lips): People who exercise should get more protein than just the RDA.
While the fear-mongering “too much protein” articles sometimes mention that bodybuilders or elite athletes need their protein, they tend to hand-wave this away as a special concern that doesn’t apply to normal people. But I think it’s worth a closer look—and honestly, this situation applies to a lot more people than just a few athletes.
Officially, there isn’t an RDA for athletes; people who exercise can stave off malnutrition with the same 0.36 grams per pound as everyone else. But that doesn’t mean that the RDA is the best target to aim for.
The International Association of Athletics Federations, which governs track and field competitions, recommends that most athletes who are maintaining or gaining weight eat 0.59 to 0.77 grams of protein per pound of bodyweight per day. That’s 101 to 131 grams for the average 171-pound woman, and 118 to 154 grams for a 200-pound man.
A group of organizations including the American College of Sports Medicine largely agrees, recommending a range from 0.54 to 0.9 grams per pound for all athletes whose weight is stable or gaining. That includes people who do endurance training like distance running, as well as strength athletes whose exercise involves mainly lifting weights. Those ranges would go as high as 153 grams for our 171-pound woman, and 180 grams for our 200-pound man.
You don’t need to be an Olympian to consider yourself an “athlete” in this sense. If you’re training for a half marathon, you’re doing plenty of distance running, and should fuel accordingly. And if you’re “just” lifting weights in the gym, but taking it seriously enough that you’re training regularly and working hard, you should consider eating in these ranges as well.
Higher-protein diets support healthy weight loss
Dieting to lose weight is not only a popular American pastime, it’s also arguably good for at least some of your health. If you’ve been on a diet recently, or if you’re planning to go on one, you aren’t a person who should settle for the RDA either.
Research shows that protein intake (and strength training—they go together!) is important to maintain muscle mass when we’re losing weight. After all, you’re aiming for fat loss, not trying to get your muscles to waste away.
For example, this study found that diets ranging from 0.48 to 0.72 grams of protein per kg of body weight (that’s 82 to 123 grams for our 171-pound woman, 96 to 144 for our 200-pound man) resulted in less weight regain after the diet, and helped people to maintain muscle mass and feel more full while they were dieting.
And if you’re losing weight and exercising? The IAAF recommends that athletes who are “undertaking high-quality weight loss” need at least 0.72 grams per pound of bodyweight, and possibly as much as 1.09 grams per pound. That would be 186 grams for a 171-pound athlete, or 218 grams for a 200-pound athlete. Most people won’t need to go that high, and it’s unclear whether athletes need to go that high. But I’m including these numbers so you see how high the ranges actually go.
Ultimately, weight loss is widely understood to be more effective and have healthier results with higher protein intakes rather than lower ones. When people focus on just eating less, without thinking about what their diet actually consists of, it’s easy to forget about protein. But the evidence suggests that you should increase protein when you’re decreasing overall calories.
Does “too much” protein turn into fat?
This is a common talking point in those articles about “too much” protein, and it’s sort of true—but it also doesn’t mean what you think it means.
When you eat more food than your body needs, your body can store it as fat. That’s true no matter what the excess is made of—protein, carbs, fat, or even alcohol. The protein you eat gets used for many different things in your body. You can build it into muscle tissue, use it for growth and repair of different kinds of cells, and so on. You can also use it for energy—basically, burning it for the calories.
So if you were eating a perfectly balanced diet, and then decided to add an extra 100 grams of protein per day, then sure, a lot of that protein would be used for energy, and since we’d have excess energy, it would get stored as fat.
But if you ate more protein, and that protein replaced other foods in your diet, then there would be no excess calories to store. Nobody is saying you should chug a couple of protein shakes on top of your regular diet. They’re saying (I’m saying) that you should plan your meals and snacks to include more protein.
For example, if your regular lunch is a turkey-and-cheese sandwich with a side of chips, you could improve the protein content of your diet by adding more turkey to the sandwich and replacing the chips with an apple. Same total calories, but more protein. As long as your total calories for the day aren’t in excess of your needs, the “extra” protein won’t get stored as fat.
Is it bad to get too much protein?
In general, high protein diets don’t have any serious health consequences. There’s a major exception, though: in some medical conditions, you may be told to limit your protein intake to protect your health.
For example, people with chronic kidney disease are often advised to use the RDA (0.36 grams per pound of body weight) as a maximum rather than a minimum. Your kidneys play a role in processing protein for excretion, so a lowered protein intake reduces the amount of work that a damaged kidney has to do. That said, once a person with chronic kidney disease begins dialysis, they may be advised to increase their protein intake for better health now that their body has help to handle the higher levels.
People with certain other disorders, like phenylketonuria and homocystinuria, may also be advised to eat a low protein diet. Obviously, if you have one of these conditions, you should be getting your dietary advice from your medical team (ask for a referral to a dietitian!) rather than from general articles on the internet.
Wasn’t there a study that said too much protein is bad?
Besides those known medical issues, the occasional findings about eating “too much” protein tend to fit into the “X is good for you/X is bad for you” ricochet news cycle. They’re not holistic assessments of protein in general on health in general, but rather specific research questions that are still being figured out.
For example, this study found that a high protein (and high fiber) diet seemed to slightly worsen one measure of insulin resistance; but it also improved metabolic health and body composition. The researchers concluded that the subjects’ body chemistry was probably just responding appropriately to the changed nutrient content of their diet. A few years later, a study of high-BMI women with insulin resistance saw improvements to their insulin resistance on a high protein diet.
Or to take another example, a study earlier this year found a link between high protein diets and atherosclerosis. But if you look at what the researchers were actually studying, they were looking at how leucine (one amino acid found in protein) affects the mTOR biochemical pathway in certain types of white blood cells. By the way, that mTOR pathway is involved in a lot more body processes than atherosclerosis, and does a lot of good things too.
So are these results interesting, and worth further study? Definitely. Worth changing protein recommendations? Only if this effect turns out (1) to actually lead to worse health outcomes, and (2) to outweigh the known benefits of higher protein. The body of evidence doesn’t support lowering protein recommendations, nor adding an upper limit.
There’s no urgent health problem that lowering our protein intake will solve
So if protein is good for us, and most of us can’t really get “too much,” why are so many people arguing that we’re overdoing it?
I think part of the reason is just misunderstanding (the writers don’t tend to have a background in nutrition and especially not in sports nutrition), but more often, I think they’re talking about a different issue entirely.
Often the “too much protein” stuff is just a way of talking about the environmental effects of meat consumption or dairy farming. People making this argument are trying to pry the double cheeseburgers out of our hands and reassuring us that we’ll be okay. I don’t think an attack on protein is an appropriate way to make that point, since plant-based proteins exist and are a fine alternative. But I understand where they’re coming from.
Ultimately, if you’re trying to make the argument that we’re eating “too much” protein for our health, you really can’t do that without some evidence that we’re eating so much protein that it’s harming our health on a widespread level. And that evidence just doesn’t exist.
To understand that point, just look at the Dietary Guidelines for Americans. This is the master document that tells us what we should be eating and what government programs should be funding. The goals include reducing rates of heart disease and diabetes, and making sure people get enough vitamins. There are Key Recommendations to limit certain nutrients—specifically sugars, saturated fats, sodium, and alcohol. There is no recommendation to reduce your intake of protein.
