Protein is referred to as the ‘building-block’ of muscle. Coupled with a great resistance training programme, consuming enough protein is critical if you want to build muscle mass.

But how much protein you need to build muscle depends on a number of factors, including your weight, body composition, activity level, age and the protein source itself.

Protein quantity is counted in grams per kilogram of bodyweight (g/kg).

Even after establishing how much protein you’ll need to put on muscle mass, be in no doubt that gaining muscle is a very slow process; this can be seen by the many thousands of DEXA scan results of Bodyscan clients who attempt to improve their lean body mass.

Also, let’s quickly illustrate how important protein really is for gaining muscle mass. In this 2012 study, a group of sedentary healthy adults were confined to a metabolic ward for ten weeks and all were fed an energy surplus 40% above their maintenance calories, with either low (0.7g/kg), medium (1.8g/kg) or high (3.0g/kg) amounts of protein.

Of course, all the individuals put on weight, thanks to the calorie surplus, but even without any resistance training or exercise, the adults fed the higher doses of protein gained about 3kg of lean body mass, which was about half of the total weight gain. Those on the lowest protein actually lost lean mass, though the loss was statistically insignificant. Interestingly, the low-protein feeders also gained the most body fat.

Protein and muscle-building – your weight and objectives.

How much protein you consume to build muscle should be based directly on your weight, not on your calorie consumption. However, your calorie consumption will be based on your weight, so the two are related.

A range of studies have shown that the amount of protein most people should aim for when building muscle is between 1.6g/kg and 2.4g/kg. So it’s no surprise that the most common rule of thumb is in the middle at 2g/kg). When it comes to calories, you may have heard that you can’t ‘force feed’ muscle gains. That is, muscle gains ‘max out’ at a certain calorie surplus, and eating in a bigger and bigger surplus will not build any more muscle bulk. The same appears to be true for how much protein you can consume before muscle gains plateau.

However, protein doses above 2.4g/kg, up to 3.3g/kg, do appear to have the benefit of minimising fat gain. So, in this respect higher protein intake seems to be beneficial for building muscle with resistance training when in a calorie surplus.

The graph below is the DEXA scan result from a male Bodyscan client who ate high doses of protein, above 2.5g/kg and gained 2.4kg of muscle mass with virtually no increase (111g) of body fat. (Also note the pace of lean gain – an average monthly increase of 651g, about one percent of total body mass each month, which is in the ‘sweet spot’ for muscle growth. Much beyond this pace in terms of bodyweight, as we see borne out in many DEXA results, we would expect to a much higher ratio of fat-to-lean.)

Similarly, if you are in a dieting (cutting) phase while building muscle long-term, higher protein (2.3g/kg to 3.3g/kg) can also help to preserve as much lean mass as possible while eating in a calorie deficit.

Gains in body weight as measured on the scale will not tell you how much is muscle and how much is fat. Regular DEXA scans every 3-4 months will reliably reveal what proportion of your weight gain is fat and what is lean mass and whether the amount of protein you are eating in your quest to build muscle is effective or not.

Protein and your body composition.

Your proportions of fat and muscle will influence how much protein you need to build muscle mass. A person with low body fat will carry more muscle mass than an overweight person of the same weight. Assuming their training programmes gain them muscle at the same rate, the leaner person will gain a greater total quantity of lean mass, and for that they need a higher amount of protein.

A DEXA scan will give an accurate and more granular picture of your body composition beyond just BMI, ‘normal weight’ and ‘overweight’. Bodyscan’s general advice on how much protein you need to build muscle is to eat 2g/kg of protein, or more when you are lean and looking to minimise fat gain.

Your protein needs change with your age

The older you get, the more your muscles are resistant to growth, so you will need more protein to encourage muscle protein synthesis (MPS). Doubling protein (from 0.8g/kg to 1.6g/kg) has been found to significantly increase lean mass in elderly men, with similar beneficial results in elderly women when protein is increased, even marginally.

Protein sources – animal vs plant.

For vegetarians and vegans, unfortunately plant-based proteins are lower quality than animal-based proteins, as determined by their bioavailability (how easy it is to digest and absorb) and its amino acid profile (how many of the nine essential amino acids (EAAs) it contains that your body cannot produce and must therefore come from food).

The lower quality of plant proteins can be overcome by eating more, or combining different sources to provide all the essential amino acids and/or supplementing with leucine, one of the most important EAAs, which plant proteins are particularly low in.

At higher doses, the effects of plant-based and animal-based protein appear to have the same effect on muscle mass, it can just be harder to consume when it comes from plants.

Some protein myths/tips

There is no evidence to suggest that higher levels of protein in the doses discussed above adversely affect liver or kidney function in healthy individuals.

It is not true that your body cannot absorb more than 30g protein in one sitting. Your body will eventually use all the protein you ingest. It is recommended, however, to have regular protein feeds (three or four) throughout the day.

Protein conclusions.

1 – The general rule of thumb of 2g/kg of protein is a good one for most people, regardless of their goals

2 – When aiming to build muscle with a resistance training regimen whilst in a calorie surplus, the amount of protein can be higher, up to 2.4g/kg.

3 – Even higher amounts of protein, up to 3.3g/kg may not see an increase in muscle mass but could well minimise fat gain and therefore be beneficial

4 – Leaner individuals with lower body fat could benefit from higher protein doses. This is because, when bulking, they will be gaining more absolute muscle mass than a fatter person of the same weight. Also, if cutting, higher protein is needed to preserve their greater lean mass.

5 – A DEXA body scan will show you exactly how much lean mass (and fat) you are gaining and therefore if the amount of protein you are eating in your bid to build muscle is effective.