Discover the ideal amount of protein you need for muscle growth.
a woman lifting weights in the gym
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Along with carbs and fats, protein is one of the three primary macronutrients essential for a healthy diet. Protein makes up approximately 20% of your body and is found in every one of your cells. Therefore, getting enough protein is critical for good health, growth and development, tissue repair, muscle building and immune function throughout life, per a 2019 article in Nutrients. However, despite the importance of protein in your diet (and for muscle growth), not everyone eats enough protein.

A topic of much debate in discussions around protein is "How much do you need to build muscle?" While there's no one-size-fits-all approach to health and fitness, it's wise to follow dietary guidelines to ensure you get enough of this muscle-building macronutrient. The international recommended dietary allowance for protein is 0.8 grams per kilogram of body weight, regardless of age and activity level, per a 2018 article in Nutrients. However, if you're looking to optimize muscle growth and recover from workouts faster, you'll need more to reach your fitness goals.

Read on to learn why protein is paramount for muscle growth and how it stacks up against carbs. Also, we'll cover how much protein you should eat, the best types of protein for building muscle and whether or not timing your protein matters.

Why Is Protein Important for Muscle Growth?

Before diving into the importance of protein for muscle growth, here's a quick refresher. When you eat protein, your body breaks it down into amino acids (the building blocks of protein). Protein comprises 20 amino acids. Eleven of them are produced by your body, and the other nine are "essential," meaning they must be acquired through diet. According to a 2020 article published in Nutrients, amino acids are necessary to repair and grow new muscle fibers. However, getting enough of each amino acid is critical for optimizing muscle protein synthesis and for your body to function properly.

Prevention of Muscle Loss

Most people think of protein as necessary only for sculpting muscles in the gym, but it's also critical for preventing muscle loss that occurs naturally as you age. In fact, a 2018 review in Ageing Research Reviews notes that around middle age, you begin to lose muscle mass (approximately 1% per year). Reda Elmardi, RD, CPT, a registered dietitian, personal trainer and owner of The Gym Goat, tells EatingWell, "As you get older, your body starts losing muscle mass faster than it gains it. Losing muscle mass can have serious consequences, including reduced mobility, increased risk of falls and decreased quality of life. Also, muscles need protein to maintain their size and strength. If you don't eat enough protein, your body will burn existing muscle tissue for fuel."

Muscle Recovery

After exercising, your body uses amino acids to rebuild damaged muscle tissue. If you're not consuming enough protein, your body cannot build muscle tissue efficiently, per a 2021 article in Nutrients. "Lacking protein can lead to poor muscle recovery after exercise," states Elmardi. "Without protein, your body will continue to break down muscle tissue after exercising instead of building it back up. Try eating foods rich in protein to keep your muscles strong and healthy. You can find these foods in meat, fish, dairy, eggs, beans, nuts, seeds and soy products."

Muscle Strength

"Protein improves muscle strength and mass. Even if you're lifting weights, your muscles won't grow or gain strength effectively if you're not eating enough protein," says Kelsey Lorencz, RDN, a registered dietitian nutritionist at Graciously Nourished. "To build muscle and strength, you need to have muscles that require repair (from physical exercise, resistance training being one of the best ways) and enough protein to strengthen muscle."

Carbs vs. Protein: Which Is Better?

Pitting carbs and protein against each other in terms of benefits for muscle growth is a null argument. Both macronutrients are essential for optimizing muscle protein synthesis and getting the most out of your workouts. Each one has its roles and functions within your body. While we've established that protein is required for muscle growth, carbs also play a vital role in building muscle. Since carbs are your body's preferred energy source, they're the primary nutrient required for fueling your workouts, states a 2022 review in Nutrients. "Eating enough carbs helps your body spare protein so that the protein you eat can go to muscle growth, not energy," explains Lorencz.

How Much Protein Should You Eat for Muscle Growth?

If you're highly active, an endurance athlete or do strength training regularly, you'll need more protein than the daily recommendation of 0.8 grams per kilogram of body weight. The exact amount you need depends on several factors, such as your age, weight and activity level. Still, the American College of Sports Medicine recommends consuming between 1.2 and 2.0 grams of protein per kilogram of body weight daily for the best results.

While the amount of protein you consume is vital for muscle growth, so is the type of protein you eat. For example, choosing plant proteins over animal proteins, when possible, can offer several health benefits. According to a 2020 study published in Nutrients, plant protein is equally effective as animal protein for building muscle. The study also found that plant protein is better for maintaining a healthy weight and reducing cardiometabolic risk factors, since animal proteins can be high in saturated fat, calories and sodium.

"Both plant and animal proteins have their advantages and drawbacks," says Elmardi. For instance, Elmardi notes that animal protein takes longer to digest than plant protein. Also, plant protein is lower in calories and fat than animal protein. Excellent plant protein sources are lentils, beans, quinoa, tofu, tempeh, edamame, nuts, seeds and seitan. Animal proteins include meat, fish, poultry, eggs and dairy. Choosing plant protein over animal protein may also lower your risk of cardiovascular disease and all-cause mortality, per a 2021 study in the International Journal of Epidemiology.

Another factor that plays a role in muscle growth is meal timing. "Meal timing is a method of eating that involves dividing your meals into three smaller portions throughout the day. This allows the body to use protein from each meal to repair muscles and build lean mass," explains Elmardi. Also, meal timing can increase muscle size and strength while reducing hunger, per a 2019 article in Nutrients.

Traditionally, it was thought that you should consume protein within your anabolic window (30 to 120 minutes after a workout) to optimize muscle repair and growth. However, recent research, as described in a 2018 article published in Frontiers in Nutrition, suggests that consistent protein intake throughout the day is the best way to maximize performance, grow muscle and promote recovery. Ideally, get 20 to 30 grams of protein over three or four meals spread evenly throughout the day. "As long as you're eating protein at meals and snacks every four to six hours throughout the day, you don't have to worry too much about eating within a specific window," says Lorencz. "However, it doesn't hurt to replenish carbohydrates and protein within an hour to two after a workout.

The Bottom Line

Protein is an essential macronutrient for fitness optimization, muscle growth, physical performance and recovery. It also helps improve strength and prevent muscle loss as you age. While protein is beneficial for recovery and building muscle, carbs also play an essential role by fueling your body and muscle cells with the energy needed for growth and repair. Get 20 to 30 grams of protein spread across three or four meals daily by eating a variety of healthy plant-based and lean animal proteins.