How Much Do We Really Need?

The importance of adequate protein intake for maintaining bone and muscle health is supported by a sizeable body of evidence. While the long-standing US recommended daily allowance (RDA) for dietary protein is 0.8 g/kg body weight per day for adults, certain populations may require more to maintain bone and muscle health.¹ For example, given the increased risks for osteoporosis and sarcopenia as bone mineral density (BMD) and muscle mass decline with age, older adults may benefit from higher protein intake than the RDA.^2,3

Based on evolving knowledge and limitations of the research from which the US protein RDA was derived, some experts have called for revision of this amount based on updated evidence that indicates increased benefits with greater protein consumption.¹ Beyond these evidence-based efforts, however, current social media trends encouraging very high levels of dietary protein⁴ may increase the risk for nutritional imbalances and associated morbidity.

In light of this recent protein craze, Rheumatology Advisor interviewed the following experts to discuss recommendations regarding dietary protein intake for optimal bone and muscle health:

• Kelly Hogan, MS, RD, CDN, registered dietitian at Hospital for Special Surgery in New York, New York;
• Cara Hall, MD, sports medicine specialist with Keck Medicine of the University of Southern California in Los Angeles;
• Ashli Greenwald MS, RDN, LDN, advance practice dietitian at Johns Hopkins Bayview Medical Center in Baltimore, Maryland; and
• Eugenia Hamshaw, MS, RDN, CDN, outpatient clinical nutrition coordinator at the Mount Sinai Kidney Center in New York, New York.

It is essential to individualize protein recommendations for each patient, and more is not always better.

There’s an ongoing trend in popular culture focused on maximizing protein consumption. How much protein is actually necessary in our diet to preserve bone and muscle in aging, and do you think some of the high-protein trends take it too far? 

Hogan: Consuming enough protein is essential for bone health and to help maintain lean muscle mass. Starting in our thirties, we naturally begin to lose lean muscle mass as we age, but lifestyle factors such as a diet adequate in protein and a regular strength training routine can help counteract this.

I do think social media content often inflates the amount of protein needed to build and maintain muscle. I often see a recommendation to consume 1.0 g of protein per pound of body weight, and that’s too much for most people. I’d typically recommend an absolute minimum of 0.8 g/kg body weight, with a more realistic recommendation for most healthy people being between 1.0 to 1.2 g/kg body weight. My recommendations are typically higher for athletes and very active people, but these are based on the individual.

Hall: As we age, the amount of protein needed increases because the body loses muscle mass and also creates anabolic resistance.^5,6 With the food industry full of highly processed foods that are not nutrient-dense, it is important for people to make sure they consume 20 to 40 g of protein per meal. After a certain point of protein intake, a ceiling is reached where more protein does not mean more benefit. Individuals with kidney disease may place more stress on the kidney if they go beyond this ceiling.⁷

I caution patients to be wary about added protein [combined with ingredients they may not desire]. I often see something labeled as protein-enriched though it may only have 5.0 g per serving — but it is labeled as 20 g counting all 4 servings. These products may also contain a ton of sugar or additives, and 4 servings may be detrimental to one’s dietary goals. Patients should be advised to always read the nutritional labels on products when possible.

Greenwald: The RDA is the amount of protein needed to meet basic metabolic needs and preserve bone and muscle as we age. If we are putting it in terms of calories, people should generally aim for 10% to 35% of overall calories to come from protein sources.⁸ Some populations have higher protein needs — such as athletes and active adults and women who are pregnant and lactating — and some people with chronic conditions need more protein to support immune function.

The average American who is looking for muscle and bone health does not necessarily need more protein than the RDA if their goal is to preserve bone and muscle health and to maintain a healthy lifestyle. 

Hamshaw: The “protein-maxxing” trend often promotes higher protein intake than is necessary for most healthy adults.⁴ At the same time, there is an evidential basis for re-examining current protein guidelines and asking whether they ought to be increased. This is especially true when it comes to protein recommendations for older adults.¹

Within the last decade, researchers have noted that the current reference ranges for dietary protein are based on data from nitrogen balance studies.⁹ Nitrogen balance studies are difficult to perform, and their findings are most applicable to young, healthy adults. The resulting protein references may be suboptimal for older adults, children, pregnant women, and the critically ill.¹

There’s another tool for determining protein needs called the indicator amino acid oxidation (IAAO) method. Researchers have used the IAAO method to measure the needs of older adults, pregnant women, and children, comparing their findings to the US RDA and other reference ranges.¹ Protein estimates derived from the IAAO method are generally higher than existing dietary references. In the case of older adults, they are consistently higher.

This is of concern because older adults are a nutritionally vulnerable population. In the US, older adults are the age-based population at most risk of developing malnutrition.¹⁰ Simultaneously, older adults are susceptible to sarcopenia. Anabolic resistance, a state in which muscles become less responsive to protein intake, is thought to increase with age.⁶

Not surprisingly, there may be a correlation between higher protein intake and preservation of lean muscle mass with aging. Epidemiological studies also point to a correlation between dietary protein intake and higher BMD.³ 

Taking these factors into consideration, researchers increasingly suggest a range of 1.0 to 1.2 g/kg/day for older adults, rather than 0.8 g/kg/day. Some recommendations are higher. Individuals with malnutrition or critical illness may benefit from protein intake in the 1.2 to 1.5 g/kg range.³

Researchers have noted that protein distribution is also important. The PROT-AGE study identified a per-meal anabolic threshold — that is, the estimated amount of protein that a person can utilize for protein synthesis from 1 meal — of 25 to 30 g for older adults.¹¹ Another study recommends 30 to 45 g per meal for optimal muscle protein synthesis, though most guidelines suggest that more than 40 grams per meal is of little to no benefit.¹²  

When it comes to counseling patients, a per-meal recommendation for protein may be more practical than a daily total. Research also suggests that an even distribution of protein intake, ranging across meals and throughout the day, is beneficial for musculoskeletal health.¹³

While these recommendations may be higher than in previous guidelines, they are not as high as some of the protein recommendations being popularized on social media. Many Americans consume more protein than necessary. High-protein diets can lead to excess consumption of both calories and saturated fat, especially if protein intake is predominantly in the form of red meat or full-fat dairy.

Meanwhile, patients with chronic kidney disease may benefit from protein intake less than 1.0 to 1.2 g/kg. It is essential to individualize protein recommendations for each patient, and more is not always better.

What are the pros and cons of using supplemental protein vs getting it from whole foods? Is adding supplementary dietary protein truly beneficial for maintaining muscle and bone health and preventing osteoporosis as we age?

Hogan: Protein supplements like bars and powders can absolutely be useful if an individual has difficulty meeting their protein needs through whole foods, and the convenience factor is also a definite pro. The cons are that they tend to be more processed and can contain added sugars, and by focusing too much on supplements we miss out on other nutrients that naturally occur in whole foods, such as vitamins, minerals, and antioxidants.

Hall: Whole foods are beneficial because they contain other macronutrients, are free of processed ingredients, have a slightly higher thermic effect, and keep people fuller longer than supplements. However, in some cases the goal may be to quickly digest and absorb protein, and supplements may be better suited for this. 

Greenwald: If a person is eating a balanced diet with adequate consumption of fruits, vegetables, whole grains, and lean protein, this should be enough to maintain muscle and bone health. However, if a person has a low dietary protein intake, increasing their protein intake via diet and or supplements would be beneficial.

There are several pros and cons of using supplemental protein vs whole food protein. Let’s start with the pros: In my practice, I often recommend using protein supplements as a meal replacement or snack. I have several patients that skip meals or often go a long time between meals and may not be getting the nutrition they need. A shake can be a good, quick, easy, and healthier option for them rather than a fast-food restaurant or a vending machine. Additionally, for people who do have higher protein requirements, supplements can be a good option to deliver the extra protein that they may not be able to obtain from their diet alone.

As for the cons, if a person is eating a healthy balanced diet, then there should be no need for an additional protein supplement. Protein shakes do not have the same complete nutritional profile as whole foods, so they are meant to supplement a balanced diet, not replace it. These products are often fortified with vitamins and minerals but are still missing some essential nutrients; therefore, solely relying on these can lead to nutritional deficiencies. Also, protein supplements can lead to side effects including digestive issues, headaches, and kidney stones. 

In addition, not all protein shakes are created equal —  some may contain contaminants such as heavy metals, which can be dangerous when consumed in large quantities. Also, many protein shakes on the market contain additives such as caffeine, creatine, and artificial sweeteners, which can also cause unwanted side effects.

Consuming lean-protein foods at meals and snacks, as well as fruits and vegetables, is a great way to maintain muscle, bone, and overall health.

Hamshaw: A pro of protein powders or high-protein snacks is ease of delivery. Older adults often eat less than younger adults due decreased appetite, taste changes, and reduced gastric motility, along with factors such as dementia or fatigue.¹⁰ Protein intake is likely to decrease as overall nutrition status declines.

Oral nutrition supplements and high protein snacks can be useful under these challenging circumstances. They offer consumers an easy means of obtaining added protein within meals or between meals and are especially helpful for individuals who have a diminished capacity to cook. For those who are struggling with poor appetite, oral nutritional supplements — including high-protein drinks and puddings — may be a more manageable protein “delivery system” than meals featuring only whole foods, which tend to be filling due to their fiber content.

For young and middle-aged adults, supplemental protein has the advantage of convenience. It’s useful for those who are trying to meet protein needs within demanding circumstances or schedules that make homemade food preparation a challenge.

For all their usefulness, protein supplements do have disadvantages. One is a missed opportunity for nutritional diversity. A complete meal featuring 25 to 30 grams of protein — such as baked chicken, fish, or tofu with a whole grain and sauteed vegetables — does not only contain protein. It also offers phytonutrients, complex carbohydrates, and whichever vitamins and minerals are specific to the vegetables on a person’s plate.

The same goes for choosing a whole food snack — such as yogurt and berries, a hard-boiled egg plus an apple, or celery with peanut butter — over a protein bar or protein powder mixed with water. If maximizing nutrient density is a goal, whole foods offer a greater return on investment than protein isolates.

Some protein supplements, especially powders and drinks, contain as much as 35 to 45 grams of protein per serving. Again, our current evidence doesn’t indicate a benefit to consuming this much protein at one time. Snacks that are manipulated to fall into the “high-protein” category may supply more protein than is useful or beneficial.

Finally, it’s important to read nutrition labels and to consider the entire nutritional profile of any protein supplement. Patients should be advised to be on the lookout for significant amounts of sugar, saturated fat, or sodium, any of which can be problematic depending on their individual health needs. For those with kidney disease, it may also be necessary to avoid phosphate additives, which are abundant in processed foods.

Could patients be lacking in other macronutrients or prone to other issues due to an overemphasis on protein?  

Hogan: Absolutely — protein is a very filling nutrient, and focusing too much on protein in meals and snacks can impact how much we are able to take in other nutrients. The biggest example I often see is fiber, because it is also a nutrient that promotes satiety and can be quite filling. Many folks I see who follow a high-protein diet are often lacking fiber in their diets because they simply have no room for it and may not understand how important it is. Fiber found in fruits, vegetables, beans, legumes, whole grains, nuts, and seeds helps regulate blood sugar and digestion and promotes gut health, which then has a positive impact on numerous aspects of health such as immunity and metabolic health.

Greenwald: Our bodies need a balance of macronutrients such as fat, carbohydrates, and protein. Without adequate intake of each of these, we risk developing essential vitamin and mineral deficiencies. 

Gut health and a healthy microbiome require a balanced diet with a lot of diversity.  Avoiding fruits and vegetables and other whole grain foods can cause an imbalance of the gut microbiome and lead to other metabolic and immune issues. 

When following a high-protein diet, people often indirectly eliminate these other foods from their diet. While it is important to get adequate protein, this macronutrient should be consumed in conjunction with other foods for the best overall health and prevention of macronutrient and micronutrient deficiencies. 

I think it is important to keep in mind that too much of any nutrient could be dangerous, and when the diet is not balanced, nutritional deficits can occur.

Hamshaw: Twenty-five or 30 g of protein within a meal should be in addition to, not at the expense of, other foods and nutrients. A balanced approach to meal planning that includes healthy fats, wholesome carbohydrates, and vegetables or fruits along with protein is still the best practice for most people.

A person who finds that protein intake is displacing an appetite for other meal components can try decreasing protein portions slightly or distributing protein intake more evenly throughout the day.

What are some general and approachable guidelines that clinicians can offer patients around protein intake — and diet in general — to help them take care of their bone and muscle health? 

Hogan: First and foremost, refer them to a dietitian! That’s what we are here for, and oftentimes a more detailed nutritional assessment is helpful for a patient to determine protein intake and meaningful ways to help increase or maintain adequate intake. Nutritional recommendations are best when they are individualized.  

However, I think a general recommendation of making sure that about one-fourth of each meal — or about one-fourth of a plate — is comprised of protein is a nice visual and general goal. And, of course, patients should be advised to avoid skipping meals or undereating, which is detrimental to bone health and maintenance of muscle mass.  

Regarding bone health, I also think most individuals benefit from vitamin D supplementation, as it is in so few foods, so checking vitamin D levels and supplementing as needed is also something I’d recommend for every patient.

Hall: I would generally recommend that patients aim to consume 20 to 40 g of protein per meal, starting at breakfast. This usually needs to be a conscious decision, as carbohydrates are much more readily available than eggs, chicken sausage, or Greek yogurt, for example. They should be advised to prioritize whole foods and use supplements when necessary, such as when they’re traveling or are really busy or if they have quick digestion. They should also spread the protein intake out throughout the day rather than all in one setting. Additionally, strength training is important to aid in muscle maintenance and growth — nutrition is just 1 building block, and the stimulus also matters.

Greenwald: I think it needs to be a lifestyle approach. Encourage patients to eat a balanced diet using the USDA MyPlate approach as a guideline — focusing on whole foods including lean proteins, fruits, vegetables, and whole grains — and eliminating processed foods and focusing more on healthy, convenient whole food options. Too much sodium from processed foods can lead to bone loss by affecting calcium absorption, and alcohol, caffeine, and dark sodas can also contribute to bone loss.^14,15  

Movement is also a very important factor for both bone and muscle health. Bone and muscle loss occur naturally as we age, and if people are not physically activity and using their muscles, there will be more of a loss. Encouraging physical activity for at least 150 minutes per week is key, with resistance training 2 to 3 times per week. Physical activity is anything that moves the body and burns calories, so this does not require a gym membership. And resistance training can include isometric exercises like Pilates or yoga, or weights or bands which are available at most major retailers and can be incorporated into a routine at home.  

Hamshaw: Think about the best way to present protein guidelines to patients: one patient may find a daily recommendation — presented as a g/kg/day total — to be orienting and helpful, while another patient may prefer to work with a protein target of 20 to 40 g per meal, adjusted to meet the person’s age and health needs.

Present recommendations in terms of food, not only in terms of numbers. Nutrition-savvy patients may appreciate working with numerical targets, but many other patients might find them to be abstract. It’s helpful to provide patients with examples of specific foods or meals that provide protein, including protein-rich breakfasts and snacks, especially if you’re trying to encourage a patient toward a more even distribution of food intake throughout the day.

If a patient wishes to track protein intake in grams, you can provide them with a list of high-protein foods or meals and their corresponding protein in grams per serving. If you need support in guiding a patient toward more protein-rich foods, consider collaborating with a registered dietitian who takes a personalized, hands-on approach to meal planning.

It is also important to consider each patient’s food preferences and traditions. The best dietary recommendations are those that a patient will actually adopt. It’s essential to recommend high-protein foods that match a patient’s existing meal patterns and preferences. Get to know your patient’s eating habits and think about realistic ways to build on the types of foods or meals that the person is already choosing.