How Much Protein Do You Need to Maximize Muscle Growth? A No-Nonsense Look at the Science

How much protein per day do you need to build muscle?

Is one gram per pound of bodyweight too much, not enough or about right?

If you eat more, are you going to build muscle faster? Or will you do just as well with less?

Let’s find out.

Since you’re reading an article about how much protein you need to build muscle, I’m going to assume a few things are true about you.

First, you’re lifting weights 3-4 days a week, and maybe doing a bit of cardio on top of that as well.

You’ve heard that more protein means more muscle, and more muscle is what you want.

What’s more, you want those gains to be made as fast as humanly possible, without wasting any time or effort in the process.

However, while you don’t want to miss out on any gains because you’re not eating enough protein, you don’t want to eat more than is strictly necessary.

Eating large amounts of protein can be expensive, as well as impractical. If you weigh 180 pounds, trying to eat 180 grams of protein each and every day isn’t easy.

How Much Protein per Day to Build Muscle?

So, with all that in mind, how much protein should you eat if you want to maximize muscle growth?

If you want a simple number to aim for, one that doesn’t involve trying to estimate your body fat percentage or decide on a target bodyweight, go for 0.7 grams per pound, or 1.6 grams per kilogram, of bodyweight.

That’s the number pulled from a “study of studies” – called a meta-analysis – that looked at the effect of protein intake and weight training on muscle growth.

The researchers pooled the results of 49 trials, covering a total of 1,863 people.

After crunching the numbers, they came to the conclusion that eating more than 1.6 grams of protein per kilogram of bodyweight (roughly 0.7 grams per pound) isn’t going to help you build muscle any faster.

How to Calculate Protein Intake for Muscle Growth

To calculate the amount of protein you need to maximize muscle growth, multiply your bodyweight in pounds by 0.7. If you prefer metric, multiply your bodyweight in kilograms by 1.6.

It is worth pointing out that the researchers don’t rule out the possibility that a higher protein intake may be beneficial.

They say:

“Given that the confidence interval of this estimate spanned from 1.03 to 2.20, it may be prudent to recommend approximately 2.2 grams of protein per kilogram of bodyweight (1 gram per pound) per day for those seeking to maximise resistance training-induced gains in fat-free mass.”

In other words, they think that the muscle-building benefits of protein plateau at around 0.7 grams per pound of bodyweight per day.

But, they acknowledge that there may be a small benefit to eating more – around 1 gram per pound of bodyweight per day, or 2.2 grams per kilogram.

How Much Protein Is Too Much?

In terms of muscle growth, there’s not much point in eating more than one gram of protein per pound of bodyweight per day. That is, going from one to 1.5 grams of protein per pound of bodyweight won’t lead to muscle being built any faster.

While protein plays an important role in helping your muscles recover and grow, there’s an upper limit on the amount that your body can use to synthesize new muscle tissue. And most research points to that upper limit being around 0.7 grams per pound, or 1.6 grams per kilogram, of bodyweight per day.

Can You Build Muscle Without Protein Supplements?

As long as you’re getting enough high-quality protein each day, you can build muscle without protein supplements. Supplements are a quick and easy way to boost your protein intake if you’re not getting enough. But there is an upper limit, over and above which additional protein isn’t going to help much.

This study, for example, shows that increasing protein intake from 0.6 to 0.9 grams per pound (1.3 to 2 grams per kilogram) of bodyweight had no effect on muscle growth in a group of untrained men.

The men trained three days a week on alternate days, using the squat, bench press, deadlift, and bent-over-row. They varied their sets and reps, doing 4 sets of 10 reps on day one (Monday or Tuesday), 6 sets of 4 reps on day two (Wednesday or Thursday), and 5 sets of 6 reps on day three (Friday or Sunday).

After 12 weeks, subjects using whey or soy to bump up their protein intake to around 160 grams per day had gained no more muscle than subjects eating an average of 106 grams of protein per day.

It’s worth mentioning that the placebo group did eat more carbs than subjects taking protein supplements, which could have affected the results via changes in glycogen/water levels.

What’s more, the combination of whey protein and resistance training did lead to an increase in satellite cell number, an effect that wasn’t seen in the other groups.

Why does that matter?

Satellite cells surround your muscle fibers, and play a key role in the synthesis of new muscle tissue. Over a longer period, those additional satellite cells may well have led to bigger, stronger muscles.

Another study, this time in a group of resistance-trained men, compared the effects of three different protein supplements – whey protein concentrate, a whey protein concentrate high in lactoferrin, and hydrolyzed whey. There was also a control group that didn’t take any protein.

Protein intake in the three supplement groups was around 0.9 grams per pound (2 grams per kilogram) of bodyweight. In the placebo group, it was 0.7 grams per pound (1.6 grams per kilogram) of bodyweight.

For eight weeks, lifters in all four groups trained four days a week, using an upper-lower split routine.

The researchers thought that subjects given whey protein would gain the most muscle.

But, they didn’t.

Whey protein, irrespective of whether it was a concentrate or a hydrolysate, was no more effective than a placebo for increasing muscle mass in previously trained young men.

Here’s how the researchers sum up their findings.

“Contrary to our hypotheses, we report that 8 weeks of heavy resistance training plus supplementation with whey protein twice daily, regardless of whey protein form or molecular weight distribution, was no more effective than placebo at increasing total body skeletal muscle mass in previously trained young men when total protein intake is removed as a potential confounding variable.”

Norwegian researchers also report that whether you get your protein from milk or whey, the muscle-building results are much the same.

Even with the use of various sophisticated methods – including DEXA, MRI and ultrasound scans – to assess muscle growth, they could find no differences between the milk and whey groups.

They say:

“Despite considerable gains in muscle mass, we were not able to show any differences in terms of muscle hypertrophy between milk and native whey supplementation.”

To repeat, protein supplements are not necessary for building muscle. They do make hitting your protein targets for the day convenient and easy, which is why I use them myself. But think of them as an optional extra, rather than a strict requirement.

Does Incomplete Protein Count Towards Your Daily Total?

Back in the day, proteins used to be classed as either complete or incomplete.

A “complete” protein is a food that supplies all eight essential amino acids in sufficient amounts to maintain tissue and support growth. With few exceptions, single foods containing complete proteins come from animal sources such as milk, meat, poultry, fish, and eggs.

An “incomplete” protein – usually found in plant sources such as grains and vegetables – is low in one or more of the essential amino acids.

The term “complete” protein is something of a misnomer. That’s because almost every source of dietary protein contains all of the essential amino acids. Some foods are just lower in certain amino acids than others.

It was once believed that all essential amino acids needed to be eaten at the same time in the same meal, and that certain foods should be eaten together in order to make a “complete” protein.

But that’s not entirely true.

Strictly speaking, it’s not necessary to combine certain foods so that you eat a complete protein with every single meal.

That’s because your body has a “protein pool” known as the free amino acid pool. This pool comes from the food you eat, as well as from the breakdown of proteins in the body.

Amino acids from your diet enter the pool from one side, while amino acids that come from protein breakdown enter the pool from the other direction. If the meal you eat is low in a particular amino acid, your body can pull it from the free amino acid pool to make up the difference.

However, the fact that this pool exists doesn’t mean that the source of protein in your diet doesn’t matter, because it does.

Specifically, there is research to show an increased rate of both protein synthesis and muscle growth with a diet containing foods that are high in BCAAs (i.e. whey protein and milk) compared with lower quality protein sources (soy).

But it’s not like foods containing an “incomplete” source of protein make zero contribution to muscle growth. They just don’t seem to do quite as good a job as the foods containing higher quality protein.

All of which is my rather long-winded way of saying that your body can still use “incomplete” protein sources to build muscle, and that both complete and incomplete sources of protein count towards your daily total.

Is Too Much Protein Bad for Your Kidneys?

The idea that a high-protein diet is “bad” for your kidneys is something that people have been arguing about for years.

It dates back to the early 1980′s when Dr Barry Brenner proposed a link between high protein diets and the progression of renal disease (renal refers to the kidneys).

It’s true that a low-protein diet helps to prevent the deterioration in renal function in patients with renal failure. That’s because one of the main jobs of the kidneys is to remove the end products of protein metabolism from your body.

They act a bit like a sieve, filtering out any unwanted substances in the blood and sending them to the bladder where they can be removed in the urine.

But the majority of scientific evidence cited by Brenner and his colleagues was generated from animal models and patients with existing renal disease.

While protein restriction may be suitable for treating someone with existing kidney disease, there is no evidence to show that high protein intakes can lead to kidney damage in healthy individuals.

A study by Belgian researchers Jacques Poortmans and Oliver Dellalieux examined the diets of young male athletes to see if their high level of protein intake had any negative impact on kidney function.

One group consisted solely of bodybuilders, while subjects in group two took part in a variety of sports, such as cycling, judo, and rowing.

On average, the bodybuilders consumed about 169 grams of protein per day (1.9 grams per kilogram of body weight). Group two consumed around 99 grams of protein daily (1.4 grams per kilogram of body weight). Some of the bodybuilders consumed up to 2.8 grams of protein per kilogram of body weight.

Despite the high levels of dietary protein, blood and urine samples showed that all markers of kidney function were well within the normal range.

Researchers from Florida’s Nova Southeastern University compared two protein intakes over a 12-month period – 2.5 grams of protein per kilogram (around 1 gram per pound) versus 3.3 grams of protein per kilogram (1.5 grams per pound) of bodyweight per day.

Protein intake averaged 214 grams per day during the normal protein phase. During the high protein phase, this rose to a whopping 284 grams per day.

Despite the extremely high levels of dietary protein in both groups, markers of kidney function remained well within the normal range.

A team of Canadian scientists reached a similar conclusion when they reviewed years of research on the subject. After looking at 28 studies on dietary protein and renal function, they found no research carried out on healthy individuals to demonstrate a clear link between increased dietary protein intake and a detrimental “strain” on the kidneys.

Here’s how they sum up their findings:

“In summary, the results of the current meta-analysis suggest a nonexistent or trivial effect of high-protein consumption on glomerular filtration rate (used to check how well the kidneys are working), in individuals with normal kidney function.

“Furthermore, there is no evidential link that shows that high protein intake somehow leads to declines in renal function in otherwise healthy persons and, as our analysis indicates, even in populations with greater risk for declines in renal function such as those with type 2 diabetes.”

Summary: How Much Protein per Day to Build Muscle?

To build muscle, aim for around 0.7 grams of protein per pound, or 1.6 grams per kilogram, of bodyweight, each day. That will do the job for most people.

There’s no reason you can’t eat more. If anything, I’d rather err on the side of eating a little too much, rather than not enough.

It’s not going to do you any harm, and there may well be a benefit to higher protein intakes, even in areas unrelated to muscle growth, such as appetite control and food intake.

However, while protein is important, there’s an upper limit on the amount that your body can use to synthesize new muscle tissue. And the science points to that upper limit being around 0.7 grams per pound, or 1.6 grams per kilogram, of bodyweight per day.

Is this the absolute maximum for every human being that has, or ever will, set foot on this planet?

No.

But, if you’re training without the benefits of pharmaceutical assistance, it is going to be there or thereabouts.

SEE ALSO: THE MUSCLE BUILDING CHEAT SHEET

If you're fed up spending hours in the gym with nothing to show for it, then check out The Muscle Building Cheat Sheet.

It's a "cut the waffle and just tell me what to do” PDF that tells you exactly how to go about building muscle. To get a copy of the cheat sheet sent to you, please enter your email address in the box below, and hit the “send it now” button.

ABOUT THE AUTHOR

Christian Finn is an exercise scientist and former “trainer to the trainers” based in the UK. He holds a masters degree in exercise science, and has been featured in or contributed to major media on two continents, including the BBC and Sunday Times in the U.K. and Men’s Health and Men’s Fitness in the U.S.