Protein for Strength Training: The Ultimate Guide

Protein! Without it, you won’t survive long. And if you get too little of it, you’ll find building muscle and performing your best quite challenging.

The word protein comes from the Greek word for “taking first place,” which perfectly reflects this nutrient’s importance. Athletes, bodybuilders, and strength athletes need more protein than average to increase performance, muscle size, and strength.

Strength training plus protein equals a more muscular and powerful you.

In this article, you’ll learn everything you need about how protein helps you build muscle and get stronger. We’ll explore how much protein you need, the best protein sources, the importance of protein timing, and much more.

Protein 101

Protein is essential for human health and plays a crucial role in many biological processes in the body. It is one of the three primary macronutrients, along with carbohydrates and fats.

You need protein from your diet to maintain and repair the cells in your body. It is especially important when you engage in strength training, as the primary role of protein is to provide the building blocks for muscle growth and recovery.

Lifting weights tells your body to build bigger muscles and get stronger. Strength training and protein act as a team. Both build muscle on their own, but together, they are more than doubly effective.

This is your muscle mass during a day when you dont lift weights:

Your lean mass stays the same because your body doesn’t need more of it.

Now look at what happens when you add strength training to your daily routine:

With resistance training added to the equation, you build significantly more muscle each time you eat a protein-rich meal, increasing your fed gains.

And who doesn’t want greater fed gains? As long as it’s muscle.

Without strength training, “fed gains” usually means more body fat, but the weights+protein combo ensures you gain quality mass.

Over time, your training and protein intake turn you into a stronger and more muscular version of yourself.

Amino Acids: the Building Blocks of Proteins

Proteins are the building blocks of your body, and amino acids are the building blocks of protein.

Amino acids are complex molecules that perform various tasks in your body, including building and repairing muscle and other tissues through protein synthesis (MPS).

In addition, they are involved in energy production, the synthesis of neurotransmitters and hormones, immune function, and numerous other functions. 

functions of protein

The protein you eat contains 20 amino acids categorized as essential or nonessential based on whether the body can synthesize them.

Protein: essential and non-essential amino acids.
Essential and non-essential amino acids.

Your body needs all 20 amino acids for health, growth, and repair. It can’t make the essential ones on its own, meaning you have to provide them through your diet.

Amino acids are bound together in chains in the protein you eat.

When you digest protein, your body breaks the chains into free amino acids.

Free amino acids vs protein
Free amino acids form different proteins.

Once they pass the intestine walls into your bloodstream, your body can use them for whatever needs to be built or repaired.

How Your Body Builds Muscle

Soon after you eat a protein-rich meal or drink a protein shake, amino acids appear in your blood. They tell your body, “Hey! It’s time to build some muscle!” 

The amino acid leucine is the one that triggers muscle protein synthesis, although your body needs them all available to build new muscle tissue.

Once the levels of leucine in your blood are high enough, your body flips the MPS switch. Amino acids from the protein you just ate and from other sources in your body are incorporated into your muscle fibers.

Lifting weights and a high protein intake mean higher muscle protein synthesis rates. Combine that with enough calories, and your muscles grow in size and strength over time.

How Much Protein Do You Need Per Day to Gain Muscle?

Consuming enough protein is essential to help your muscles recover and grow bigger and stronger.

General guidelines from US and European authorities recommend a daily protein intake of around 0.8 grams per kilogram (0.36 grams per pound) of body weight. That’s enough for the average person who performs a limited amount of physical activity.

You can build muscle by eating only that amount of protein, but it’s far from optimal. You’ll find muscle growth slow and your recovery sub-par.

When the experts set the current recommendations for protein, they didn’t factor strength training and building muscle into the equation. You, however, probably do. If you want your lifting to pay off properly, you need more protein than a sedentary person.

  • The American College of Sports Medicine recommends 1.2–1.7 grams of protein per kilogram, or 0.5 to 0.8 grams per pound, of body weight per day, for active individuals who want to increase muscle mass.1
  • According to the International Society of Sports Nutrition, strength athletes and resistance-trained individuals who want to build muscle should aim for at least 1.4–2.0 g protein/kg (0.65–0.91 grams per pound) body weight/day.2
  • Finally, a systematic review published in the British Journal of Sports Medicine finds that 1.6–2.2 grams of protein per kg (0.7–1 gram per pound) of body weight per day optimize gains in muscle mass.3

The easiest way to figure out how much protein you need is to use our nifty protein calculator!

>> Protein Calculator for Weight Loss and Muscle Gain

In summary:

  • Eat at least 1.2 grams of protein per kilogram of body weight per day.
  • Eating 1.4 g/kg/d is likely even better.
  • Consuming up to 2.2 g/kg/d ensures your muscles have access to the protein they need for optimal gains in muscle mass.

Read more:

>> How Much Protein Do You Need per Day to Gain Muscle?

How Much Protein Do You Need on a Weight-Loss Diet?

During a weight-loss diet, your protein needs increase if you want to maintain your hard-earned muscle mass or, at the very least, minimize muscle loss.

Dieting for weight loss is a misnomer if your goal is to improve your body composition. Losing weight overall is less important than losing body fat. And if you’re dieting for athletic performance or to look your best, maintaining muscle mass is crucial.

Let’s take two identical twins with the same body fat percentage and amount of muscle mass.

You put them on weight-loss diets with similar calorie deficit goals. The difference is that twin number one doesn’t care about how much protein he consumes and bases his diet on donuts. Twin number two eats a balanced diet high in protein.

The result? Both twins lose similar amounts of body weight, but the one who made sure to eat plenty of protein maintains significantly more muscle.

The combination of resistance exercise and a high-protein diet allows you to retain muscle when dieting for fat loss. If you do everything right, you might gain muscle and lose fat at the same time.

On the other hand, a weight-loss diet with little protein and no lifting can result in a 50/50 fat loss/muscle loss scenario. You’re lighter, sure, but your body composition is no better than before, and your muscle strength has probably gone down.

If you have a lot of body fat to lose or are overweight or obese, a daily protein intake of around 2 grams per kg (0.91 grams per pound) of lean body mass (LBM) is the sweet spot. You don’t need to go higher because your high body fat percentage protects your lean muscle mass at this point.

Once you’re leaner, or if you start your diet relatively lean but want to get shredded, you need to up your protein intake.

Go for a protein intake of 2.3–3.1 grams per kilogram (1.04–1.4 grams per pound) of lean body mass per day during a calorie deficit to maintain your hard-earned muscle. As you get leaner, aim for the higher end of that interval.

The reason for basing your protein needs on lean body mass instead of the total body weight when dieting for weight loss is that your fat tissue is not metabolically demanding. If you carry a lot of body fat and calculate the protein content of your low-calorie fat-loss diet on your total body weight, chances are you’re not going to eat much more than protein. You lose out on other nutrient-rich foods, and your diet gets bland.

In addition to helping you maintain your lean body mass, a high-protein enables you to keep your hunger in check during a calorie deficit, protein being the most satiating macronutrient.

In summary:

  • During a fat-loss diet, your protein needs increase.
  • A protein intake of at least 2 grams per kg of lean body mass helps protect your muscle during a calorie deficit.
  • If you’re already lean and trying to lose that last stubborn body fat, 2.3–3.1 grams of protein per kg lean body mass is beneficial.

Read more:

>> How to Cut: Lose Fat and Keep Your Muscle Mass

>> How to Cut for Bodybuilding: Top 12 Tips for Success

>> How Long to Cut for Bodybuilding

>> Macros for Cutting: Count Your Way to Fat Loss

>> How to Build Muscle and Lose Fat at the Same Time

How Much Protein Per Meal Can You Use to Build Muscle Mass?

Can you eat your daily protein intake in one or two sittings and absorb it all?

Yes, you do not pee or poop out the protein if you eat a lot at once. That’s a myth.

However, doing so is not the best idea if you want to build muscle as effectively as possible. How much protein you can use to build muscle differs from how much protein you can absorb.

Consuming 30 to 40 grams of high-quality protein per serving maximizes muscle protein synthesis. If you eat more in one sitting, nothing terrible happens, and you still absorb everything, but your body isn’t going to use all of it to build muscle.

For example, a serving of 340 grams of lean meat (90 grams of protein) is only as effective as 113 grams (30 grams of protein).

protein in meal for muscle protein synthesis

So, what happens to the protein if you consume more than you can use for muscle protein synthesis?

That protein does not go to waste. Instead, two things happen:

  • Your body uses it to build and repair other tissues, like your gut, skin, intestines, liver, and other organs. That’s not a bad thing, but it won’t contribute to your skeletal muscle development.
  • Protein breakdown decreases. How much of that is muscle protein breakdown is unknown. Measuring muscle protein breakdown is difficult. Your muscles grow when muscle protein synthesis exceeds muscle protein breakdown, so decreasing it could be a plus.

After a weight training workout, 20 grams of protein maximize muscle protein synthesis if you’ve trained a muscle group or two. After a full-body workout, your muscles can use twice that amount, 40 grams, in one serving.

protein: 20 vs 40 grams of

An easy way to split your daily protein intake is to consume 0.4 g/kg/meal (≈0.2g/pound) across a minimum of four meals. That way, you reach the amount of protein needed to optimize gains in muscle mass with a balanced meal plan of breakfast, lunch, dinner, and a snack.

If you prefer to eat all your protein in a few hefty meals, don’t worry. You don’t have to disrupt your lifestyle. 

Spreading your protein feedings over the day might be slightly better, but you likely won’t see any significant differences in muscle mass gains if you “only” eat two or three meals instead. The most important thing is the total protein content of your diet.

The rise in popularity of intermittent fasting shows that concentrating your meals to only a few hours allows you to build an impressive, muscular body. However, if you’re aiming for competitive bodybuilding, it’s likely a good idea to spread your protein intake relatively evenly over the day.

In summary:

  • Thirty to forty grams of protein per serving maximizes muscle protein synthesis.
  • Larger servings don’t go to waste but won’t provide any additional benefit for building muscle.
  • Consuming 0.4 g/kg/meal across a minimum of four meals is a convenient way to optimize your protein intake. If you need even more protein, up your serving sizes a little, or add a protein shake or two during the day.

Read more:

>> How Much Protein Per Meal Can You Use to Build Muscle Mass?

Is It Important to Eat or Drink Protein Quickly after Training?

One of the most common practices of bodybuilders is to drink a protein shake immediately after a training session. It only makes sense: you need protein to build muscle, and why waste time after a workout?

But do you need to gulp protein down after training? Is it even necessary?

When you haven’t eaten in some time – you’re in the fasted state – your muscle protein breakdown exceeds muscle protein synthesis (MPS). In other words, your muscle protein balance is negative: you’re losing muscle. Oh no! But don’t worry; an hour or two here or there is unimportant.

If you lift weights while fasting, you stimulate MPS. However, your muscle protein balance can’t turn positive until you consume protein. It becomes less negative, but you don’t start building muscle until you eat.

Combining strength training with protein, be it a proper meal or a shake, boosts muscle protein enough that it overtakes muscle breakdown, and you start adding lean muscle mass.

eating for muscle growth

That sounds like eating or drinking protein right after your training session is the best way to go.

And it probably is, but it doesn’t make any practical difference. You see, your body is more intelligent than that.

Following a strength-training session, your amino acid sensitivity is elevated for at least 24 hours. That means each time you consume protein during that time, you build more muscle than you would have if you hadn’t worked out.

Over the day as a whole, it makes little difference if you consume protein immediately following your training sessions or wait a bit.

Research shows that athletes who consume protein within the first hour after working out do not build more muscle than those who wait two hours or more.4

Now, if the protein shake you chugged right after finishing your last set means your total protein intake for the day went up, you’ll likely build more muscle. But you could consume that extra protein at any other time for the same muscle-building effect.

Your total daily protein intake is, by far, the most crucial factor. Not if you consume protein immediately after your gym session or wait until you get home.

Of course, you could take things to the extreme to the point where it affects your muscle growth negatively.

Let’s say you train in the morning without eating breakfast. You’ve fasted for at least eight hours before heading to the gym, and then you continue to fast for another 8–10 hours before eating your only protein meal of the day. Then, most likely, you wouldn’t be able to compensate for the prolonged fasting. At the very least, you’d rob yourself of gains.

A practical approach would be to eat 20–40 grams of high-quality protein before and after your workout to ensure your muscles have access to the amino acids they need to build muscle.

However, you don’t have to time those protein intakes to the minute. You can separate your pre-and post-workout meals by approximately 3–4 hours and train somewhere within that time. If you train between two major meals, like breakfast and lunch or lunch and dinner, you can safely extend that interval to 5–6 hours.

Your body can use protein from a meal you ate before working out to build muscle after the session. If you’ve already eaten plenty of protein the hours before your gym session, you’re not in any hurry to consume even more after your last set.

Working out fasting before breakfast is no problem. But if you do, it’s more important to consume some protein within a reasonable timeframe afterward.

In summary:

  • Your body needs protein to start building muscle after a workout.
  • You don’t have to rush to gulp down a shake after training, as your body responds better to protein for many hours after a workout session.
  • You’re good to go if you separate your pre-and post-workout protein intakes by 3–4 hours. If we’re talking large meals like lunch and dinner, up to six hours is no problem.

Read more:

>> Is It Important to Eat or Drink Protein Quickly after Training?

What Are the Best Protein Sources for Gaining Muscle?

Not all protein sources are created equal. Some contain higher amounts of the essential amino acids you need to build muscle than others.

If a protein provides enough essential amino acids, it’s considered a complete protein.

In general, animal-based proteins like meat, dairy, and eggs contain more amino acids needed for muscle growth.

Most plant proteins are incomplete, meaning they provide insufficient amounts of one or more of the essential acids. There are a few exceptions, like soy protein, quinoa, and buckwheat.

animal protein and plant protein

You might think that a diet that doesn’t provide plenty of protein from animal sources is inferior for building muscle.

Fortunately, your body is more intelligent than that.

If you eat any type of animal protein with plant foods, you don’t have to worry about protein quality.

You automatically combine amino acids from different protein sources, even if you don’t eat them in the same meal. Two or more lower-quality proteins become one high-quality protein your body can use to create new muscle tissue.

You don’t have to plan things out and combine different proteins. Your body takes care of it for you as long as you eat a reasonably varied diet.

The amino acid leucine is the one that triggers muscle protein synthesis. You need around three grams, the amount you get from 20–25 grams of whey protein, to maximize MPS.

You need to eat more of a plant-based source that provides less leucine to get the same anabolic response. For example, you’d have to eat 33 grams of potato protein, 37 grams of protein from brown rice, 38 grams of pea protein, or 40 grams of soy protein.

In theory, you could get all your protein from one plant-based source and still get the amino acids you need for building muscle.

protein amount from different sources

Of course, if potatoes were your primary protein source, you’d likely get sick of them before long.

Overall, animal sources are the ones with the highest protein quality. Here is a list of protein sources loosely ranked for muscle-building potential.

  • Milk and dairy products (milk, yogurt, cheese, cottage cheese, greek yogurt, quark, casein- and whey protein powder)
  • Eggs
  • Red meat (beef, pork, lamb, game, ostrich)
  • White meat (chicken, turkey)
  • Fish and seafood
  • Soy-based foods (tofu, tempeh, edamame, soy protein powder)
  • Quinoa
  • Beans, lentils
  • Nuts, almonds, seeds
  • Grains

Using dairy product or eggs, consuming milk, yogurt, cheese, or eggs, even in small amounts, with plant foods, makes doubly sure you get enough essential amino acids to help maximize protein synthesis.

If you enjoy the vegan lifestyle, there is an easy trick you can use to make your plant-based diet as effective for building muscle as an omnivore diet.

Simply increase your protein intake by 25% compared to standard recommendations. That way, you get as many essential amino acids your body needs to build muscle as someone who eats animal proteins.

In summary:

  • In general, animal-based proteins provide more amino acids you need to build muscle than plant-based proteins.
  • Eating an omnivorous diet means you don’t have to think about protein quality.
  • For vegan lifters, simply upping your protein intake by 25% ensures you get enough.

Read more:

>> Eating for Muscle Growth: When, What, and How Much

Which Is the Best Protein Powder for Building Muscle?

Let’s clarify: you don’t need protein powder to build muscle.

You’ll see no difference in muscle gain between getting your protein from regular food and a combination of food and protein shakes. A gram of protein is a gram of protein, whether from an egg or a whey protein shake.

That being said, protein powders can be very convenient. Sometimes you don’t have the time or opportunity to sit down for a proper meal. Scoop some protein powder into a shaker, add water, and you’re good to go.

In addition, protein powders make it easy to maintain a high-protein diet. Protein-rich foods are filling, and consuming the right amount of protein from food alone can be challenging, especially during a bulk. For many, drinking a shake to increase their protein intake is much easier than eating another steak. Often less expensive, too.

Research shows that participants receiving a protein supplement gain 27% more fat-free mass than control groups.3 Again, there is no magic behind a protein supplement, but the convenience is hard to beat.

Decades ago, protein powder used to taste like chalk and be about as soluble. Nowadays, they come in a variety of flavors, and you’re sure to find one that suits your taste buds. Or you can get unflavored and unsweetened protein powders if you want.

Plant-based protein powders include:

  • Soy protein
  • Hemp protein
  • Rice protein
  • Pea protein
  • Nut or seed protein
  • Vegan-friendly protein blends that include several different plant-based protein sources

Animal-based options include:

  • Whey protein
  • Casein protein
  • Milk protein (a combination of whey and casein protein)
  • Beef protein
  • Egg protein, most often egg white protein

The three most well-researched protein powders are whey, casein, and soy protein.

Whey and casein are dairy proteins from regular cow’s milk. Soy protein comes from, not surprisingly, the soybean.

Several studies compare the three for boosting muscle protein synthesis.

whey vs casein vs soy protein

According to some research, whey protein maximizes lean body mass gain compared to other protein supplements. Animal protein, in general, tends to be more beneficial for lean mass than plant protein.5

However, you can still build muscle effectively if you don’t use animal products.

Remember that your total protein intake is the most important factor, not which protein powder you use. Indeed, some studies suggest that soy protein supplements are similarly effective as whey protein for muscle mass and strength gains.6

The research on other protein powders is limited but suggests that pea protein, beef protein, rice protein, potato protein, and egg protein are all helpful for boosting muscle protein synthesis and building bigger and stronger muscles.

Before bedtime, a casein protein shake is beneficial to maintain muscle protein synthesis overnight. Further research is needed to determine if pre-sleep protein supplementation helps improve your body composition long-term.

In summary:

  • Whey is the most versatile protein supplement and the best option for most people.
  • Casein protein is a popular pre-sleep protein supplement that helps keep MPS elevated overnight.
  • Soy protein supplements are the most well-researched plant-based alternative, although other options like pea protein also work well.

Read more:

>> Whey Protein: The Complete Guide to the Most Popular Protein Supplement for Strength Athletes

>> Whey Protein Concentrate vs. Isolate: What’s The Difference?

>> Casein: Fast Gains from Slow Protein?

>> Soy – Healthy Alternative to Meat or Toxic Hormonal Disruptor?

>> Whey or Soy Protein for Building Muscle?

Whey vs. BCAA/EAA: Which Is Better?

To build muscle, you need all the essential amino acids in adequate amounts.

A complete protein like whey protein provides them all, and 20–25 grams of whey maximizes muscle protein synthesis.

Branched-chain amino acid supplements only contain three essential amino acids: leucine, isoleucine, and valine.


They are enough to tell your body to start building muscle, but not much happens without the rest of the building blocks.

EAA supplements work fine for boosting MPS. They provide everything your body needs to create new proteins but don’t offer any benefits over whey apart from being lower in calories per serving.

BCAA supplements only stimulate muscle protein synthesis 50% as effectively as whey protein and fail to sustain MPS over time. Also, there is no evidence that BCAAs help you gain muscle and strength or reduce muscle breakdown.

bcaa vs whey protein

In summary:

  • Whey protein is always superior to branched-chain aminos for building muscle, as the BCAAs alone cannot support increased muscle protein synthesis rates.
  • Essential amino-acid supplements are effective for boosting MPS but have no known benefits over whey protein.

Read more:

>> BCAA Supplements: Benefits and Side Effects

>> Whey Protein vs. BCAA: Which is Better?

>> BCAA vs. EAA: Which Is Better For Your Gains?

Protein for Older Adults

As we age, our protein requirements change, and older people benefit from higher protein intakes than young adults. In addition, you need more dietary protein per serving to maximize muscle protein synthesis and gain lean muscle.

The recommended dietary allowance for protein (0.8 grams per kg or 0.36 grams per pound of body weight per day) is not enough for older adults with an active lifestyle. You need up to 1.3 grams of protein per kilogram (0.6 grams per pound) of body weight per day. And that’s to maintain your muscle tissue and prevent age-related declines in lean mass.

Your total protein intake should be at least that of young people to support your efforts in the gym and gain muscle size and strength. That means aiming for a minimum of 1.3 grams per kg body weight. Consuming 1.6–2.2 grams of protein per kg of body weight per day is even better for optimizing gains in muscle mass.

The average person loses 0.5% to 1.5% lean body mass annually between 50 and 80. But you can prevent that with regular resistance training and a high total protein intake!

What about protein shakes for men and women over 50? It can be challenging to reach a high protein intake from your diet alone, especially as many people experience decreased appetite as they age.

That’s where protein supplements can help.

A protein shake after your training session is convenient and makes it easy to meet your protein needs.

The best overall protein powder for healthy adults over 50 is whey protein, with soy protein an excellent alternative if you don’t use dairy products or want a plant-based option. Both provide all the essential amino acids you need to build muscle.

In summary:

  • Seniors need more protein than young people, both in general and for muscle gains.
  • Aiming for the upper end of the 1.6–2.2 grams of protein/kg/day recommendation is a good idea.
  • Whey and soy protein supplements are both excellent options for the older lifter.

Read more:

>> Building Muscle as You Age: Protein Needs for the Older Lifter

>> The Best Protein Powder for Men and Women Over 50

Are High-Protein Diets Safe?

For decades, scientists and doctors debated whether a high-protein diet could lead to health problems.

Previous studies on animals suggest that overeating protein could be bad for your kidneys, detrimental to your bone health, and even increase the risk of some cancers.

Fortunately, human studies do not support such theories.

No Tolerable Upper Intake Level for protein consumption has been established, and no adverse consequences (including cancer, kidney disease, kidney stones, and osteoporosis) of high protein intakes have been identified.7

In healthy humans, the addition of extra protein when you already eat enough to support growth and repair means that it is used for energy.

If you already have certain medical conditions, like decreased kidney function, you should get professional medical advice before upping your protein intake. However, for healthy adults, no evidence suggests eating a lot of protein will cause such issues.

That being said, there could be some indirect health consequences of eating “too much” protein.

  • Your diet might become so protein-heavy that you miss out on other foods that provide valuable nutrients.
  • Some high-protein sources can be highly processed, increasing cancer risk and other diseases. Not because of the protein but because of the additives and processing.8

The solution? Base your high protein diet on a varied selection of mainly unprocessed, nutritious protein sources, and don’t ignore the quality of your carbs and fats.

A diet high in protein can be a healthy diet. As long as the quality of your overall diet is high, there are no known health issues with eating plenty of it.

In summary:

There are no known adverse effects of high-protein diets in healthy adults.

Take-Home Message

Protein is important. Make sure to consume enough of it.

Want to learn more about dietary supplements? Which ones are worth your money, and which are questionable or useless? Check our StrengthLog’s Supplement Guide, our free guide where I review 26 of the most popular supplements.


  1. ACSM Information on Protein Intake for Optimal Muscle Maintenance.
  2. Journal of the International Society of Sports Nutrition, Volume 14, Article number: 20 (2017). International Society of Sports Nutrition Position Stand: protein and exercise.
  3. Br J Sports Med. 2018 Mar;52(6):376-384. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults.
  4. Journal of the International Society of Sports Nutrition volume 10, Article number: 53 (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis.
  5. Nutrients 2021, 13(2), 661. Animal Protein versus Plant Protein in Supporting Lean Mass and Muscle Strength: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
  6. Int J Sport Nutr Exerc Metab. 2018 Nov 1;28(6):674-685. No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise.
  7. Gropper SS, Smith JL, Carr TP. Advanced Nutrition and Human Metabolism. Eighth ed. Boston MA: Cengage Learning; 2022.
  8. World Cancer Research Fund International’s Global Cancer Update Programme: Meat, Fish, Dairy and Cancer Risk.