Protein Is Vital for Building Muscle. Here's How to Work out How Much You Need
Let's face it, protein and muscle-building go hand-in-hand. The macronutrient is vital for muscle tissue repair and is made of amino acids: the building blocks of strength. But, with sources, calculations and advice varying wildly, few of us actually know how much protein we need to build muscle, optimise performance in the gym and maintain those coveted gains.
And without that knowledge, the caricature of the gym bro guzzling a protein shake that's surgically attached to him is allowed to live on. Well, no more. We're here to tell you exactly how much protein you need to build muscle, as well as explain how you can calculate a protein intake that's personalised to you and the foods you can add to your diet to up your protein numbers if necessary.
But, before we do, we need to make two things clear. The first is that you can eat as much protein as you like, as often as you like, but if you’re not in the gym working out at the correct intensity, your muscles will reach a growth limit pretty rapidly. The second is that it’s important to remember that we’re all different, with different goals and different workout routines – and the amount of protein you need is unlikely to be the same as your best mate. With that in mind, let's get to it.
What's The Recommended Daily Allowance For Protein?
In the UK, adults are advised to eat 0.75g of protein for each kilogram they weigh, based on the Reference Nutrient Intake (RNI). So, for example, if you weigh 70kg (11 stone), you should eat about 52.5g of protein a day.
This is seen as the bare minimum to help prevent any adverse health effects from protein deficiencies (think: brittle nails and hair, fatigue, diarrhoea).
Some evidence suggests that 1.2 to 1.6 g/kg of high-quality protein is actually the sweet spot when it comes to achieving optimal health.
What Protein Is and Why It's Important
Before we work out how much protein you need to build muscle, let's first break down exactly what protein is.
Put simply, protein is a macronutrient (a nutrient that we need in larger quantities) that is built from amino acids, which are stitched together into long chains. Some of these chains your body can make naturally – known as 'non-essential’ – and some of which it can’t.
These are called ‘essential’ amino acids and you need to source them from food. When you chow down on a chicken breast your body breaks proteins down into their constituent amino acids, which it then uses to build everything from new muscle to organs and hair.
Why Protein Is Important for Building Muscle
To build muscle, your body needs to synthesise more muscle protein than it breaks down, which is why anyone looking to build muscle needs to make sure they're getting enough protein, as well as making sure they're putting the work in on the gym floor.
It's not just us saying that, there's a body of research that confirms the part protein plays in building muscle. A study published in the journal Nutrients, for example, found that ‘protein intake was shown to promote additional gains in lean body mass beyond those observed with resistance exercise alone.’
Why Protein Is Important for Weight Loss
As well as being good for building strength, protein also plays an important role in losing weight. Evidence suggests that eating protein can both increase the number of calories you burn, by stimulating your metabolic rate, as well as reduce your appetite, meaning you're less likely to put on pounds in the first place.
What's more, a study by researchers at Maastricht University reported that even a modest increase in protein, from 15% to 18% of calories, reduced the number of fat people regained after weight loss by 50%.
Evidence suggests that going above 2.2g/kg of protein per day will help to preserve lean body mass to a greater extent and optimise athletic goals.
Are You Getting Enough Protein?
As mentioned, the recommended dietary allowance suggests that you should eat a modest 0.75g of protein daily per kg of body weight. If you're not already aware, let us be the first to tell you: that's not enough to really pack on muscle.
In fact, if you’re trying to build muscle and are training consistently, then you need to be aiming for 1.6–2.2g/kg of protein per day to ensure you grow at the maximum rate.
In real food terms, 1.6g/kg would equate to 128g protein – which is equivalent to two chicken breasts and a pint of milk. If you’re vegan, this could look like a soy protein drink, a block of tofu, a cup of lentils and some oats.
'Elite athletes eat around 2g per kg every day,' says Dr Karen Reid, a sports science nutritionist who's worked with the Wales rugby team, and the founder of Performance Food.
She recommends getting near that level for the first 12 weeks of a new workout programme. 'That’s when you’re sore and you’re breaking down muscle fibres and creating new structures.' Remember, damage plus fuel equals growth. After 12 weeks, she recommends scaling back to between 1.2g and 1.6g per kilo.
Why You Shouldn't Calculate How Much Protein You Need Based on Total Calories or Bodyweight
On a simple level, protein guidelines generally fall into one of two camps: a proportion either of how much you eat or how much you weigh. However, both have drawbacks.
Take only eating a specific percentage of protein. The problem is that the numbers are going to be impacted in a big way by your total calorie intake. For example, 30 per cent protein on a 2000-calorie diet (600 calories) is very different from 30 per cent protein on a 4000-calorie diet (1200 calories) despite the fact that the percentages are exactly the same: 150g a day compared to 300g a day.
So, calculating your protein intake relative to your weight could be better, as it stays consistent regardless of how many calories you're packing in.
For example, if you were to eat 2g of protein per kilo of body weight, you'll be fuelling yourself with the same amount of protein regardless of your total daily calorie count — whether that's 1500 or 4000. However, this system is also not without its flaws.
How to Calculate Your Protein Needs
Perhaps, then, the best way to measure how much protein you need to consume daily is based on 'lean body mass', this is essentially everything on your body that isn't body fat, including your muscles and skeleton. This could provide a more accurate figure than focusing on just your total weight.
Of course, if you’re a fitness model sitting comfortably at nine per cent body fat, then there’s obviously not going to be much difference whether protein intake is expressed relative to your weight or lean body mass. For the average guy, however, it's a considerably different story (since you’re likely to be carrying more weight around your midriff and have a higher body-fat percentage).
On the flip side, let's look at an obese man who weighs 135kg. In this case, it would be unwise to base his protein intake on his total body weight. Using the 2g of protein per kg, he'll be eating a whopping 270g of protein on a daily basis.
Needless to say, our hypothetical overweight man definitely doesn’t need to be eating the equivalent of 10 chicken breasts a day, even if he's looking to build muscle. In fact, most research shows little benefit to consuming more than 2.2g of protein per kg of lean body mass.
If you weigh 90kg with 20 per cent body fat, you have 72kg of lean body mass. Multiply that number by 2.2, and you get a daily protein target of 158g per day. If you weigh 90 kilograms with 10 per cent body fat, you have 81 kilograms of lean body mass. Multiply that by 2.2, and you get 178 grams of protein per day. Far more realistically achieved by upping your steak and eggs intake.
How To Calculate Your Protein Requirements Based on Height
If you're not sure how to estimate your lean body mass in order to calculate your protein goals, coach and nutritionist Brad Pilon offers a much simpler heuristic: simply use your height. 'I'm a firm believer that height matters more than weight when it comes to calculating how much protein you should eat, because of the obvious confounder of body fat,' Pilon says.
His take is that, broadly speaking, your height is much more indicative of how much muscle mass you're carrying than how much you workout, 'A 6'4" guy who's an absolute string bean of a human being will probably still have more muscle and lean body mass than a jacked 5'10" guy,' Pilon adds.
Pilon advocates that you start with a simple baseline of 50g of protein for a 5-foot-tall person, and then factor in an additional 7g for every inch of height. This means a 5'10'' man would be aiming for around 120g of protein each day.
This may seem low versus the previous methods of calculations, but Pilon points out that early studies conducted on protein requirements already had a built-in 'buffer' for those with higher requirements such as bodybuilders, and that the additional research has simply added a 'buffer to the buffer', ramping up to targets that Pilon perceives to be protein overkill.
Of course, you can eat more protein to taste and bump it up if you feel as though your training necessitates it, but Pilon's simple heuristic offers a great starting point for calculating your target, regardless of your body fat percentage.
How Much Protein Do I Need to Build Muscle?
For any guy who has been training for several years, they could theoretically get away with less daily protein. That's because the closer you are to your genetic limit in terms of muscle growth, the slower the gains will come. And the slower your rate of growth, the less protein you need to support that growth.
In short, if you’re trying to gain muscle, or even if you just want to hold on to the muscle you have while you drop fat, 2.2g of protein per kg of lean body mass is plenty.
You can eat more if you like. However, bear in mind that it’s not going to make much difference to the speed at which you gain muscle and will make a difference not only to your bank balance, but potentially your waistline too.
Protein Calculator
If you’re just looking for optimal health, you should aim to consume:
1.2g-1.6g of protein per kg of body mass
If you're trying to put on muscle and you're training consistently, then aim for:
1.6-2.2g of protein per kg of body mass
If you think you have more than 5-10kg to lose, calculate your protein needs using your height and use the following equation:
50g of protein for a 5-foot tall person, add 7g for every inch of height
Best High-Protein Foods for Building Muscle
Need to up your protein intake? Look no further than the following foods.
Chicken Breast: 33g of protein per 100g
Cod: 18g of protein per 100g
Whey Protein: 80 to 90g of protein per 100g
Vegan Protein: 70 to 80g of protein per 100g
Clams and Other Molluscs: 48g of protein per 100g
Low-sodium Parmesan Cheese: 42g of protein per 100g
Tofu: 17g of protein per 100g
Lean Beef: 36g of protein per 100g
Lamb: 25g of protein per 100g
Pork Tenderloin: 23g of protein per 100g
Soya Protein Isolate: 88g of protein per 100g
Eggs: 12.5g of protein per 100g
Grilled Salmon: 24.2g of protein per 100g
Tuna: 23g of protein per 100g
Grilled pork chop: 31g per 100g
When to Eat Protein
Contrary to popular wisdom in bodybuilding circles when you eat your protein is far less impactful than simply ensuring that you're eating enough throughout the day. Recent studies have indicated that when it comes to adding size and strength, rushing to the locker room to down a lukewarm post-workout protein shake doesn't offer much of a benefit over simply aiming to consistently hit your protein target each day, regardless of the timings.
Another myth we're happy to bust is the idea that your body can only ingest 20-30 grams of protein in a single sitting and that any extra is effectively 'wasted'. New evidence published in Cell Reports Medicine supports that there is no upper limit to our protein absorption post-resistance training. Your body has the ability to absorb, and use, any whole food source you consume, especially protein. As to whether or not that protein will be put to use boosting your bench press or pumping up your pecs is another matter, but your body will put it to good use, regardless.
Whilst some research does back up the argument that spreading your protein evenly throughout the day aids in 'muscle protein synthesis' – that is, the building of new muscle tissue – ultimately it's the overall quantity of protein you consume consistently that's going to be the biggest determiner of improvements in size and strength.
It's also worth noting that the evidence by exercise researcher Brad Schoenfeld, who suggests that in order to gain muscle mass, you should consume 0.4g/kg per meal across a minimum of four meals in the day, is based on research done on fast-digesting proteins in the absence of other macronutrients (but people don't really eat like that...)
So, the general consensus is, try to spread out your protein into 30-40 gram servings if you can, but don't be afraid to go a little higher if that helps you to stay on track. Total protein intake in the day is by far the key driver of muscle growth.
Are You Eating Too Much Protein?
While we want you to get enough protein in your diet, it may be possible to have too much of a good thing.
Although studies have shown that humans can safely ingest over 2g of protein per kg of body weight for long periods of time, and even that elite cyclists can consume up to 3g of protein per kg with no ill effects, there may still be an upper limit. In trials where participants were asked to consume 4.4g of protein per kg of body weight, many subjects reported an inability to consume this high amount with some complaining of gastrointestinal distress. These subjects dropped out of the study, however, it should be noted that the remaining participants reported no side effects over an 8-week period, indicating that the upper limit (for healthy adults) could be as much as twice as high as previously thought.
Although high-protein diets could present a risk for those with existing kidney conditions, where protein intake could exacerbate the problem, for healthy individuals, current research suggests that moderate to high protein intake does not pose a significant risk to kidney health.
With that being said, protein intake beyond the safe upper limits can, over time, exceed the ability of the liver, intestine to detoxify ammonia, a byproduct of protein digestion, which can lead to adverse effects. Side effects of a chronic protein overdose can include intestinal discomfort, hyperammonemia, hyperinsulinemia, dehydration, irritation, nausea, diarrhoea, and liver injuries.
Issues around high protein intake can be additionally exacerbated by a coincident low intake of carbohydrates. The additional burden on both the liver and kidney to produce glucose (usually rendered from the carbohydrates we eat), can prove too much, leading to illness and even organ failure.
Symptoms of overconsumption of protein can include stomach pains, nausea, vomiting, fatigue and headaches- all worthy of a doctor's visit.
However, the amount of protein necessary to cause severely adverse side effects in otherwise healthy humans, is pretty significant, with the average person who exercises regularly having to consume well over 350-400g of protein daily over a course of months to even be in the at-risk range.
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