Is there such a thing as too much protein?

New federal dietary guidelines and social media influencers certainly make protein-centric lifestyles seem like the right option. But a UNLV nutrition expert says the answer is more nuanced; it depends on the individual and what they hope to accomplish with their protein intake.

“There is no ideal absolute amount of protein you should consume. The requirements are relative to the person and are dependent on several factors,” says Sara Rosenkranz, a kinesiology and nutrition sciences professor with UNLV’s School of Integrated Health Sciences. 

The recommended 10%-35% of your daily caloric intake from protein is a wide range that Rosenkranz says allows for flexibility in the amount of protein you consume each day. 

She has long studied the interactions between nutrition and physical activity, as well as the influence of lifestyle on cardiovascular and metabolic health. Her research has examined the body's ability to digest starch, metabolic responses to high-fat meals with or without previous bouts of exercise, how eating strawberries impacts health, and the ways sedentary behavior affects chronic disease health outcomes.

How Protein Fuels the Body

Protein is a fundamental building block for the body, crucial for building and repairing tissues (muscles, bones, skin), creating enzymes and hormones, supporting immune function, and transporting nutrients. 

For those recovering from illness, adding protein helps with repair and immune function. As we get older, there is also a greater need for protein to help slow muscle loss. Every decade after age 30, we lose 3-8% of our muscle mass, a number Rosenkranz says accelerates even more after age 60.

And while there is a caloric advantage to protein, Rosenkranz warns against consuming more than you should. Adding extra protein to what you already eat, especially through liquid supplements or calorie-dense high-protein foods, can add body fat along with that muscle.

“Some people view protein as free calories, but that isn’t the case,” she says. 

Go too heavy on the protein, and you risk pushing out other nutrients, like fiber, which is essential for digestive health, controlling blood glucose and lipids, and reducing the risk of most common chronic diseases.  

“We know that adequate fiber, which is associated with positive health in the long term, is a much more prevalent deficiency than our protein consumption,” Rosenkranz says.

According to the 0.8g/kg of body weight recommendation, a person who weighs 180 pounds would need approximately 65 grams of protein each day, though adjustments should be made depending on age, activity level, health status, energy balance, and more.

For athletes trying to cut calories, a greater emphasis on protein will help them do just that, with some evidence showing that they might need to exceed 1.6g/kg/day to avoid loss of lean body mass.

“As long as you don’t have chronic kidney disease, there’s not much risk of doubling the recommended dietary allowance (RDA) each day,” Rosenkranz says. “But there is concern if you go three to four times the recommended RDA, because it’s likely to push out other nutrients that we need.”

For those with kidney disease, Rosenkranz recommends a higher quality of protein spread throughout the day to make it more digestible. If you do have chronic kidney disease, she recommends speaking with a registered dietitian to get tailored recommendations.

The Influence of Influencers

Social media influencers, specifically those pushing an animal-based, protein-heavy diet, have made it difficult for nutrition experts to educate the public on the proper ways to give your body enough protein without overdoing it.

The popularity of protein-heavy social media videos has led to a greater demand by the public, which companies have been quick to recognize. Brands like PepsiCo, General Mills, Starbucks, Chipotle, and others have all created products to meet the protein-crazed moment, with protein-focused products increasing dramatically over the past decade.

Rosenkranz says it is important for consumers to read the labels to see what else the products contain. At times, the protein content is not much different from the original but comes with additional calories and sugar, or less of other healthful ingredients like fiber. 

“Rather than pushing high-protein diets per se, I’m more concerned about the quality of the protein and the particular diet to support your goals,” she says.

Digesting the New Federal Guidelines

The federal government’s recent revision of the food pyramid, the first since 2011, now prioritizes protein, dairy, and healthy fats while placing less emphasis on whole grains, a reversal of the longstanding recommendations. 

Adding to the confusion, Rosenkranz says the revised pyramid does not significantly change the protein recommendations she would make, particularly for people trying to lose weight while maintaining muscle mass and for older adults.

But not all proteins are the same. Rosenkranz cautions against loading up with excessive amounts of whey protein shakes or bars, products that lack the proper amount of fiber and other nutrients our bodies need. 

“It is also important to ensure that you have adequate carbohydrates because they can help decrease muscle breakdown and allow protein to be used for important purposes aside from providing energy,” she explains. “Protein is for more than just muscle.”

And animal-based proteins, as emphasized by the new federal guidelines, do not offer the same protections against poor metabolic health outcomes as plant-based proteins, she says. 

Animal fats are typically higher in saturated fats, particularly some of the saturated fats that are implicated in higher risk for cardiovascular and metabolic diseases. 

Not all saturated fats have been shown to be harmful, she adds, just some that are commonly consumed in the American diet.

Non-animal Protein Options

As a lifelong vegetarian, Rosenkranz is no stranger to people asking her how she gets her daily protein.

“I let people know that it is actually not difficult, and pose a question back to them for consideration: How do non-vegetarians get their fiber? Or phytonutrients, vitamins, and some minerals?” she says. “Your body is really good at combining the essential amino acids that it needs to function. So, as long as you consume a variety of different plant-based foods, inadequacy of essential amino acids is really not a concern.”

Rosenkranz recommends incorporating some of the non-animal protein options available to get the proper amount of protein without pushing out the other essential nutrients.

Foods like tempeh, tofu, quinoa, edamame, legumes, beans, nuts, seeds, and whole grain are all beneficial. 

“You also have great sources of fiber from fruits, vegetables, brown rice, and whole-grain bread. Many of these foods are also pretty high in protein,” she says.