Optimal protein intake for bulking & cutting - Building muscle and losing fat.

Science broken down

Ah protein.

Chances are you’re aware of the “importance of protein” in relationship to muscle growth and repair. Nowadays everybody’s drinking protein shakes, eating protein enhanced food and/or increasing their consumption of proteins such as chicken, fish, eggs etc in their diet. But is it really necessary?

Proteins are responsible for quite a lot in the human body, a lot more than we’re going to cover in this article that’s for sure…

Protein is a part of every cell in the human body, whether that be muscle, nails, hair, bones etc. On top of this, proteins help regulate certain hormones, make up antibodies, but most importantly for the fitness fanatic – helps repair and build muscle tissue after exercise (and maintain new muscle once it has been “built”).

Protein is definitely very useful and it would be wise to consume enough of it in your diet.

The question is; how much is enough protein?


 1 gram of protein contains 4kcals (calories).

Proteins are made up of long chains of amino acids.

 There are 20 amino acids, 9 of which are considered “essential”, meaning the body cannot synthesise them effectively & must be supplied through diet.

Proteins are considered “complete” if they provide all essential amino acids (all animal/fish proteins contain all EAAs).

Before we break down some numbers, I’m going to make an assumption about yourself: you are currently resistance training. Simply put, if you are not resistance training, you should be (applies to both men and women). The benefits are vast and the visual impact it has on your physique is unparalleled (i.e. cardio will very rarely suffice in building a great looking body). Because you are resistance training, your protein requirements are now higher than the average sedentary individual. 

The recommended daily amount (RDA) for adults.

The current RDA for adults lies around 0.8g protein per kg of bodyweight, which, is not only considerably below what is required of resistance trained individuals (yourselves), but has also been implied to be too low even for the average population [1].

Having said this however, it isn’t like extremely high protein intakes are necessary to promote muscle growth, you could consume the RDA of 0.8g per kg and still make progress, just not as much progress as you could make with a higher intake (in theory). This value of around 0.8g per kg of bodyweight can be considered a somewhat minimum amount for day to day health.

In research terms, the way in which this is usually determined is to measure the level of protein intake that corresponds to “zero nitrogen balance”, i.e. neither positive or negative.

As protein synthesis requires a positive nitrogen balance, we can deduce that an individual training for hypertrophy, strength and/or endurance would require a higher protein intake than what is required to achieve a zero nitrogen balance [2].

Basically, resistance-trained individuals require more protein than the RDA for the average population.

Protein intake for “bulking” (calorie surplus).

So if you’re in a state of caloric surplus, whether it be a large or small surplus (I always recommend a small/moderate surplus over a large surplus), your focus is on building muscle/strength.

That’s not to say you’re going to get absolutely massive any time soon (don’t worry ladies), but that you’re attempting to be in an “anabolic state” where muscle growth can occur without much compromise. Simply put, you’re actively not trying to lose body fat or “maintain”.

Because of the higher calorie intake when bulking, protein requirements actually tend to be lower than when calorie deprived.

Why? The body can effectively recover with greater ease when in a calorie surplus, as there are more “resources” (energy) to provide the body with, and therefore the need to break down protein is less than when in a caloric deficit.

Remember, any time you’re in a calorie surplus, you’re literally above your energy demands every single day (on average).

“Myth busting”

There has been the general rule in the fitness to consume 1g per lb of bodyweight for a while now, and I don’t particularly have a big problem with this rule of thumb – I just think it has gained a lot of popularity due to its mathematical simplicity (“170lbs? Eat 170g, simple”).

One problem with this is an individual with a little bit more bodyfat on their frame, may for example find themselves adhering to this rule and consuming over 200grams per day (for example). This is almost definitely unnecessarily high, as there will be no further benefit to extra protein past a certain point and will also be financially draining. 

Protein is also a very satiating macronutrient and can cause people to struggle to consume enough calories when “bulking”, so why over-consume (unless you have a massive appetite, like myself)?

Most of the research out there suggests that for resistance trained athletes, there is no real benefit past the point of around 1.8g protein per kg of bodyweight in terms of muscle gained – which is less than the 1g per lb rule [3] [4] [5] [6]. However, there are studies out there that infer some kind of benefit (albeit a small one) to slightly higher levels of protein, particularly when in a caloric deficit (more on this later).

As a guideline range, I’d say that aiming to consume between 1.5g and 2.2g per kg of bodyweight will be sufficient for muscle gain. Reason for this is I do feel like, although potentially not beneficial, hitting between 1.5 and 2.2g per kg allows you to err on the side of caution – no gains left behind. Plus, in a caloric surplus there is less concern about dampening your carbohydrate and fat consumption via increased protein intake, as your caloric intake is already above your energy needs (not the case when cutting).

A small caveat though, for an individual carrying more bodyfat (like previously mentioned), it may make more sense to perform this calculation on one’s lean body mass (LBM), so more like 1.7-2.4g per kg of LBM. This is probably only a concern when cutting though because most people at a high bodyfat percentage will not be trying to gain weight.

Bottom line:

You see, 2.2g per kg of bodyweight (the highest I would recommend for athletes who are in a caloric surplus seeking muscle growth) is roughly 1g per lb of bodyweight, the “industry standard”.

The difference is, I’m prescribing this almost as a maximum: something you could consume to err on the side of caution, not because of the increases in hypertrophy it will cause (as this has not been proven).

For the overwhelming majority of us, I would hypothesise that we could achieve all potential hypertrophy by consuming around 1.8g of protein per kg of bodyweight, and if we were to go even lower than this, we would likely see no real decreases in hypertrophy. This study actually found that protein requirements for athletes could actually be not particularly different from the RDA [7].

Whilst I’d still stick to a higher protein intake than suggested in the study above, it can be liberating to know that if you consume a lower protein diet from time to time, you will not be losing all of your gains.

Infographic courtesy of  www.strengthandconditioningresearch.com

Protein intake for “cutting” (calorie deficit).

There is a reasonably strong amount of evidence to show that protein requirements are actually higher when in a caloric deficit for a prolonged period (cutting weight) [8].

The intuition behind this is not particularly complex – when in a state of negative energy balance, the body now begins to call upon protein as a source of energy, and therefore amino acids (proteins) are broken down more effectively due to the increased demand for them.

As this breakdown in protein places the individual at risk of muscle loss (very common over a prolonged dieting phase), increases in protein are often necessary to try and facilitate retentions/increases in lean body mass.

How much to consume?

The previous recommendation of around 1.5g-2.2g per kg of bodyweight is still valid, particularly for those who are not currently very lean and/or haven’t been dieting for a prolonged period. However, staying towards the higher end of that range, and even surpassing it (up to around 3g per kg) may be perfectly valid, particularly as you get leaner/diet longer [4]. This review from Eric Helms found that “protein needs for energy-restricted athletes are likely 2.3-3.1g per kg of LBM, scaled upwards with severity of caloric restriction and leanness” [9]

My recommendation for cutting: 

Protein has not only shown to be beneficial in promoting lean body mass retention when in a caloric deficit, it is also a far more satiating macronutrient (it makes you feel less hungry), making a high protein diet a solid candidate for a cutting phase.

I personally would recommend an individual begins their diet between 1.8-2.2g per kg of bodyweight if they are currently holidng more bodyfat (if considerably overweight, base the calculation off your lean body mass and not total body mass), and gradually scale that up to between 2.5-3g per kg of lean bodyweight as you reach the end of a cutting phase and your bodyfat percentage is very low.

However, given that most individuals will not be dieting down to an unhealthy level of bodyfat, a max intake of around 2.8g per kg of lean bodyweight will likely be more than sufficient. This also helps ensure that you don’t dampen your carb and fat intake too much, due to the potentially anabolic nature of them macronutrients as well.

Infographic courtesy of  www.strengthandconditioningresearch.com


1.5grams – 2.2grams per kg of bodyweight.

For individuals who struggle to gain weight on a bulk, opt towards the lower range.

For individuals who tend to gain too much bodyfat on a bulk, opt towards the higher range.

Higher protein intakes are fine but likely not beneficial for muscle mass gains.


1.8grams – 2.8grams per kg of lean bodyweight.

Protein intake should be scaled up as body fat gets lower/diet gets longer (higher bodyfat = less “need” for more protein)

Higher protein intakes promote better satiety and can help retain muscle mass.

Be wary to not increase protein so high that carbs & fats become unnecessarily low (problematic).

Below is a little infographic from my instagram – be sure to follow me there for more informative content and to follow my own fitness journey – @lukeknightspt.

For those interested in purchasing a protein supplement to help you reach your daily protein goals – I highly recommend this protein from MyProtein – Good quality, extremely good value for money & many flavours available to choose from.

For a comprehensive overview of macronutrients for fat loss (including protein) – check out the article here | Guidelines for different body-types.


  • [1]  Elango R, Humayun MA, Ball RO, Pencharz PB. Evidence that protein requirements have been significantly underestimated. Curr Opin Clin Nutr Metab Care. 2010 Jan.
  • [2] Resnick M, Tennent D, Patzowski J, Johnson AE. Optimal Protein Intake in Athletes – Review. Texas Orthopedic Journal.
    Recommended reading ^.
  • [3] Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci. 2004 Jan. 
  • [4] Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011. 
  • [5] Mark A. Tarnopolsky. Building muscle: nutrition to maximize bulk and strength adaptations to resistance exercise training. European Journal of Sport Science, Vol 8. Mar 2008. 
  • [6] Lemon PW, Beyond the zone: protein needs of active individuals. J Am Coll Nutr, 2000 Oct.
  • [7] Phillips SM. Protein requirements and supplementation in strength sports. Nutrition. 2004 Jul-Aug.
  • [8] Phillips SM. Dietary protein for athletes: from requirements to metabolic advantage. Appl Physiol Nutr Metab. 2006 Dec.
  • [9] Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab. 2014 Apr.

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