
Can You Build Muscle Just by Eating Protein?
Protein is key for muscle gains, but the macro can’t work alone. Here’s why.
By Jennifer Heimlich•
Does Protein Build Muscle Without Working Out?
How Much Protein to Aim for While Strength Training
What Happens If You Eat a Lot of Protein Without Working Out?
The Takeaway
If you’re looking to build up some muscle, there’s one piece of nutrition advice you’ll hear over and over again: Make sure you eat enough protein. “In order for muscles to grow, protein needs to be available in adequate amounts,” says Kelly Jones, RD, a sports dietitian for pro athletes and active families. Otherwise, your body won’t have the building blocks—in the form of amino acids from protein—that it needs to create new muscle tissue.
But what about the opposite scenario: Does protein build muscle without working out? As in, could eating a protein-heavy diet lead to gains even without strength training? We spoke to top sports nutrition experts to learn more about the role protein plays in developing muscle and what it can mean for your muscles if you don’t exercise.
Does Protein Build Muscle Without Working Out?
Scarfing down protein without working out might help you maintain some of your baseline muscle mass—but it won’t help you build more. Without the stress of exercise, nothing’s signaling to the body that it needs to build more robust muscles, Jones explains.
Remember: Muscle growth only happens after we actually break down the muscle fibers a little bit through exercise. As our bodies repair this normal damage, our muscles grow back bigger and stronger.
“We create this stimulus to tell our body, ‘Hey, we’re going to keep moving all this weight—maybe we make a bigger, stronger muscle to do that,’” says Chad Kerksick, PhD, an associate professor of exercise science at Lindenwood University. Without working out, though, we never send our muscles that message.
The Role Protein Plays In Muscle Growth
So, if exercise is really what kickstarts those strength gains, why is protein such a big part of the equation?
Well, muscle tissue is created through a process called muscle protein synthesis. This is where the amino acids from the protein we eat are put to work to create new muscle tissue.
Making sure we have adequate protein to fuel this process is essential because, as Kerksick explains, protein works differently in our body than either fat or carbs. “We have proteins in every single tissue in our body, and our body constantly is turning them over,” he says. Our bodies can store carbs and fat, but protein is something we need to regularly ingest to meet the demands of that daily turnover. Otherwise, our bodies will cannibalize our muscles themselves to supply the protein needed to function.
When we exercise, we speed up that turnover process. “And that demands more protein,” Kerksick says. (More on that below!) So no matter how much you’re lifting, without eating that extra protein, “eventually, progress will plateau,” Jones says. “And with age, muscle loss is actually likely, especially for women during perimenopause and in menopause.”
How Much Protein to Aim for While Strength Training
The official recommended daily allowance for protein in the United States is 0.8 grams per kilogram of body weight. But Kerksick (alongside many other experts) points out that that number is really just the bare minimum that’s suggested in order to prevent disease—it’s not the optimal amount, especially if you’re looking to grow muscle.
For healthy, active people who are trying to build or maintain muscle mass, the International Society of Sports Nutrition recommends consuming between 1.4 and 2 grams of protein per kilogram of body weight per day. (To figure out how much you weigh in kilograms, divide your weight in pounds by 2.2.)
Aside from your workout regimen, Jones says there are a number of factors that can affect exactly how much protein you need, such as your age, fitness and health goals, whether you need to manage blood sugar for chronic disease, and whether you’re pregnant, breastfeeding, or in perimenopause or menopause.
But no matter your circumstances—including how much strength training you do—some health experts say that the majority of Americans get all the protein they need without thinking twice about it. “There are a number of studies that tell us that people generally do a pretty good job of getting protein anyway,” Kerksick says.
One thing to keep an eye on, however, is the type of protein you’re eating. “Past just having enough total protein, we can maximize muscle protein synthesis by having enough of one amino acid in particular, called leucine,” Jones says. She explains that leucine is known as a “trigger” to kickstart muscle protein synthesis and is found in foods like dairy, poultry, eggs, and salmon. (Vegans can get their fill through soy foods, or by combining certain plant foods like wheat pasta and lentils or oats and pumpkin seeds, Jones says.)
It also might be helpful to try to eat some protein within a couple hours of finishing up your workout. Although experts used to put a big emphasis on refueling right after a cooldown, they’ve since found that timing really only matters for athletes on the extreme end of the spectrum when it comes to workout intensity and volume. “But there’s absolutely zero evidence to tell us that taking advantage of timing is bad,” Kerksick says.
To him, that means you might as well try to get a good, healthy dose of amino acids after your workout, though you probably don’t have to race to down a protein shake, either.

Westend61 / Westend61 via Getty Images
What Happens If You Eat a Lot of Protein Without Working Out?
Generally, having a little extra protein in your diet when you’re not working out isn’t a major issue. The biggest downside is that it can stress out the kidneys (particularly if that protein comes from animal sources), so those with kidney issues may want to be more mindful.
Just know that a couple different things can happen to that extra protein when it doesn’t get put to work building muscle. Since our bodies can’t store protein, if we eat a bunch more than we need and our carbohydrate intake is also low—say you’ve been skipping all bread and pasta in favor of plain chicken, for instance—the amino acids from protein can be broken down and used for energy, but this isn’t an ideal energy source. On the other hand, if we’re eating so much protein that we’re getting more total calories than our body burns, those calories will be stored as fat.
Whether you’re working out or not, it’s also important to remember that protein isn’t the only nutrient our bodies need to thrive. “When intake is excessive, it often means protein is displacing other nutrients,” Jones says. You could end up missing out on fruits and veggies, or legumes and whole grains which provide essential vitamins, minerals, fiber, and antioxidants.
“In other cases, when people emphasize large amounts of animal proteins, it can lead to excessive intake of fat and saturated fat, which can have a negative impact on heart health long term,” Jones adds.
Long story short? It’s important to eat enough protein, but don’t go overboard. Getting enough carbs and healthy fats in your diet is crucial in order to maintain a balanced diet.
Related Articles

Health
This Is How Long It Takes to Build Muscle, According to 4 Fitness Pros

Nutrition
How Much Protein Should You Eat to Gain Muscle?

Health
Can You ‘Optimize’ Muscle Protein Synthesis to Gain More Muscle? Experts Weigh In

Strength Train
The Pros and Cons of Training to Failure—Plus How to Do It Properly
The Takeaway
If you’re looking to build muscle, protein is definitely a key component of the equation. But if you’re wondering whether protein builds muscle without working out, the answer is no. It doesn’t matter how many ribeye steaks you eat—if you don’t challenge your muscles enough to cause the breakdown that triggers muscle protein synthesis, you won’t increase your muscle mass.
Meanwhile, be sure not to forget about the rest of your diet, either. Even if you’re taking in the right amount of protein, if you don’t eat enough total calories, “protein will be converted into an energy source rather than being used for muscle growth and repair,” Jones says.
The ticket to building muscles is to combine consistent strength workouts (the Peloton App is full of great options) with a well-rounded diet that’s got ample protein, but also a healthy amount of carbs and fat.

Peloton App
Access thousands of classes with no equipment needed.
This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.
Get our latest health stories straight to your inbox
Enter your email to get articles, expert-backed tips, and updates from Peloton sent to your inbox.
By providing your email address, you agree to receive marketing communications from Peloton.
For more about how we use your information, see our Privacy Policy.