How much protein should you consume?

All of it bro...

Author

Mark Christie
August 26, 2024 • Estimated Reading Time: 11 minutes

All of it bro… the general advice most are given and follow has been a simple, 1g per pound of bodyweight.

While this recommendation within the evidence based fitness community is simple for everyone to follow, is there any scientific basis for the 1g per pound of bodyweight advice?

We will cover what the science says, and recommendations for certain demographics who may want to eat more, perhaps your on a calorie restriction, or perhaps your already consuming more than you actually need!

IN THIS ARTICLE:

PROTEIN BRO
How Much Per Day?

Adequate protein consumption is required to maintain a positive nitrogen balance in the body and prevent muscle loss. Amino Acids are the building blocks of protein which is the building blocks of your skeletal muscle afterall!

For reference: all of these studies have been carried out on natural subjects, meaning those who are not using anabolics. Performance enhancing drugs can increase how much protein your body can consume and get a use out of, due to their effects on Muscle Protein Synthesis.

The below studies also do not take into consideration extreme levels of body fat on both sides of the scale, meaning very lean or very overweight.

A systematic review with meta analysis and meta regression by (Morton et al., 2017), compared data from 49 different studies which included a total of 1863 participants and found that higher protein intakes resulted in greater fat free mass until an intake of 1.6g per kg of bodyweight per day, on average, where above 1.6g/kg had no meaningful benefit. It’s worth noting that these results are for the average/mean optimal protein intake.

The solid arrow found the bottom of Figure A’s chart (below) represents the authors Confidence Interval (CI). With a 95% CI ranging for protein intakes between 1.03 to 2.2g per kg of bodyweight per day.

Note - Metric to Imperial: 2.2g/kg = 1g/lbs

So if you really wanted to ensure you were eating enough, you could intake as high as 1g/lbs (2.2g/kg), however this likely isn’t required.

Figure A: From (Morton et al., 2017) - Segmental linear regression between relative total protein intake (g/kg body mass/day) and the change in fat-free mass (ΔFFM).

A 2022 meta-analysis of randomised controlled trials, published in the Journal of Sports Medicine by (Tagawa et al., 2022) looked at data from 69 studies, using a dose response analysis with a spline model on muscle strength. They came to the conclusion that per 0.1g per kg of bodyweight, strength gains increased until a total protein intake of, 1.5g per kg of bodyweight. After which, no further gains were observed. As shown in Figure B, from the meta analysis.

Figure B: From (Tagawa et al., 2022) - Spline curves illustrating the associations between total protein intake and change% in muscle strength

A study by (Hoffman et al., 2006), looked at the effects of different protein intake levels on 23 collegiate strength / power athletes over a 12 week period. They were split into 3 groups consuming either 1-1.4g, 1.6-1.8g or 2g per kg of bodyweight per day. The results showed no difference between the groups in gains in body mass, lean body mass or fat mass. 1RM squat and 1RM bench also saw no difference between groups. The conclusion of the study was that there is no evidence to support greater protein intakes over the recommended level of 1.6-1.8g per kg of bodyweight.

BUT I’M ON A CUT
Restricted Calories and Dieting Protein Recommendations.

A review by (Phillips & Van Loon, 2011), came to the conclusion that 1.3g-1.8g per kg of bodyweight consumed through 3-4 meals was sufficient enough to maximise Muscle Protein Synthesis. Interestingly they state protein ranges of 1.8-2.0g per kg of bodyweight may be beneficial against lean mass loss during calorie restriction diets for fat loss.

Another Study by (Mettler et al., 2010) published in the Medicine & Science in Sports & Exercise Journal, took 20 resistance trained athletes and split them into two groups, one (the control group) consumed a protein intake of 1 g/kg, while the other consumed 2.3 g/kg. The high-protein group lost significantly less LBM (0.3 kg) over the course of the two week intervention compared to the low-protein group (1.6 kg).

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In our healthy, trained, lean subjects, we found a loss of lean body mass, which was substantially larger than the loss of fat mass, when the control diet was consumed. However, with higher protein intake, lean body mass loss was ∼20% of that of the control group.

Study Authors: (Mettler et al., 2010)

Authors note that unlike similar studies that have increased protein intake at the expense of reducing carbohydrate intake, they opted to decrease fat intake to increase the protein allowance for the study subjects.

Figure C: From (Mettler et al., 2010)

A Study by (Walberg et al., 1988) looked at the effects of two energy restricted diets with different protein intakes in 19 lean, male, non-competitive bodybuilders. One group consumed a protein intake of 0.8 g/kg and higher carbohydrates, while the other consumed 1.6 g/kg of protein with lower carbohydrates. Although only lasted one week, nitrogen losses occurred only in the lower protein group and LBM decreased by a mean of 2.7 kg in the 0.8 g/kg protein group and by a mean of 1.4 kg in the 1.6 g/kg protein group. While the higher protein group lessened LBM losses compared to the low protein group, they were not eliminated.

I LIKE VEG
Recommendations For Vegans

Daily requirements of protein consumption may need to increase on a vegan diet due to the low DIAAS scores associated with some of the protein sources typically consumed. Essentially, a lot of vegan food sources do not have a complete amino acid profile and have low bioavailability.

A Study by (Gorissen et al., 2016), found you can offset the lower DIAAS score when comparing wheat protein to casein protein, by just consuming more of it. This suggests that Vegans may require higher protein diets than people who mostly consume animal protein sources, unless they are eating complete plant based protein sources, such as: Pea Protein isolate, Soy etc. We covered this in a previous issue which you can read 👉 here.

A review by (Iraki et al., 2019) found that protein quality may only become a concern if consuming on the lower end range of protein guidelines 1.6g/kg per day. Authors also state that it may be beneficial to supplement with leucine and EAA rich sources of protein, e.g. pea protein.

JUST FOR YOU
Key Takeaways and Practical Applications

  • Recommended protein intakes range from ~1.5g/kg - 1.8g/kg per day

  • When on an energy restrictive diet (calorie deficit) several studies have show a benefit to going as high as 2.2g/kg which equates to 1g/lbs of bodyweight.

  • For people who follow a vegan diet, sticking to the upper recommended intakes has been shown to negate the lower quality protein found in popular vegan protein sources.

  • Supplementing with high quality vegan protein sources such a pea isolate or soy isolate or EAA’s may be beneficial.

As long as you aim for 1.6g/kg per day, from quality protein sources, most of you should be covered. Box ticked, if you will.

If you feel you want to just make sure you are hitting enough required protein, you can increase it to 1g/lbs (2.2g/kg) but for most this shouldn’t be necessary.

With regards to “cutting” or being in a calorie deficit, the larger systematic review by (Morton et al., 2017) which included 1863 subjects, found a confidence interval in protein intakes upto 2.2g/kg (1g/lbs). On top of this, several smaller studies have found benefits in LBM retention upto 2.3g/kg per day. You may want to intake the higher range end of the recommended protein intake during a fat loss / energy restriction phase to preserve as much lean body mass as possible. The goal is to lose fat after all, not muscle.