Does Protein Give You Energy? Dietitians Break It Down

We all know and love protein for helping us get stronger and driving fitness gains. In fact, its muscle-building power is largely why the macronutrient is often touted as an optimal element of a post-workout snack. It can also help keep our hair looking shiny, our bones strong, and our stomachs full. 

But does protein give you energy? We talked to registered dietitians to find out its role in fueling our bodies.

Does Protein Give You Energy?

The foods we eat and the liquids we drink rev us up—they hold a lot of stored chemical energy that our body later breaks down into smaller pieces to use as fuel. This energy comes from three key macronutrients: carbs, fat, and protein.

So, yes, protein can give us energy. But it’s also not the most efficient source of energy out of the three, says Destini Moody, RD, a sports performance dietitian with Garage Gym Reviews. “Carbs, fat, and protein are all macronutrients that give food their calories, and anything with calories gives some type of energy,” she says.

Carbs are the energy powerhouse here. That’s because they go through the shortest metabolic cycle as the body breaks them down to produce glucose as fuel, which Moody says the body runs best on. In short, carbs are the quickest macronutrient to digest and provide the fastest source of energy. 

But if the body isn’t getting enough glucose from carbs, it starts looking for energy elsewhere. It first gets a little help from fats, which are more energy-rich but take a while to process. Protein is next in line. In this scenario, your body may convert dietary protein into ketone bodies, which are acids that replace glucose as fuel, Moody explains. 

But this is a survival mechanism and definitely isn’t the optimal way for your body to run, she says. It may break down muscle tissue and use those proteins for energy in more extended periods of undernutrition. A 2021 study published in the journal Frontiers in Molecular Neuroscience found that the body may also utilize protein as an energy source in the event of intense exercise and medical conditions such as diabetes.

But Moody reiterates that this isn’t ideal for most people. “To put it simply, though protein does provide calories, it’s not typically involved in the energy-making process except in cases where the body is lacking nutrition in other areas,” she says. 

This is why carbs are such a crucial part of our diets—and why they’re a key element of a great pre-exercise meal or snack. The Dietary Guidelines for Americans recommends that 45–65 percent of your daily calories come from carbs.

How Much Energy Do You Get from Protein?

One gram of protein provides up to four calories, the same as carbs. But because protein isn’t our primary source of fuel, it only satisfies a small portion of our energy needs and increases slightly if we need to tap into that reserve. According to an excerpt from sports dietitian  Suzanne Girard Eberle’s book Endurance Sports Nutrition, protein typically provides up to 5 percent of our energy needs. But when we’re undergoing intense exercise, it can supply up to 15 percent of those needs.

For perspective, protein generally comprises 10–35 percent of our daily calories. The National Academy of Medicine recommends an intake of just 0.8 grams of protein per kilogram of body weight each day for the average healthy adult. But the International Society of Sports Nutrition recommends that active individuals, especially those looking to build muscle and optimize recovery, get more than that—around 1.4–2 grams of protein per kilogram of their body weight each day.

Other Key Functions of Protein

Even though protein’s main role isn’t to give you energy, it’s still important for your body. “Protein is responsible for providing the structural elements of all cells in the body and is well known for its role in maintaining and building tissues and muscle,” says Alex Larson, RDN, a registered dietitian nutritionist focused on sports nutrition. “It also plays a role in all chemical reactions in the body and helps to regulate the immune system.”

Too little protein means your body isn’t getting enough amino acids, which weakens muscles and can leave you feeling drained and fatigued, Moody adds. In this sense, it contributes to our energy levels in a more indirect way.

Protein can help us:

The Takeaway

Protein isn’t the body’s ideal energy source—carbs are. But when the body isn’t getting enough glucose from carbs, whether we’re not eating enough of them or working out intensely, it turns to protein as a backup energy source. In this process, the protein is broken down into amino acids that are later converted to carbs or fat to be used as energy. This is a survival mechanism that can break down lean muscle mass, and it isn’t the ideal way for our bodies to run. 

But protein is still important to add to your diet to maintain high energy levels. It helps us maintain steady blood sugar levels and ensures we get enough amino acids. These are both indirect ways protein fuels us; otherwise, exercising can quickly leave us feeling fatigued. Protein can also help build muscle, support a healthy metabolism rate, and boost the immune system. Just make sure it’s part of a well-rounded diet complete with carbs and fat to reap the benefits of all three macronutrients. 

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.