Estimated reading time: 6mins
First things first… why is protein important?
Those involved in strenuous activities, particularly weight training and bodybuilding, may benefit from a greater intake of protein than those not involved in these activities.
When you lift those heavy weights at the gym you’re actually causing muscle damage in the form of microscopic tears. This is where protein comes in. Consuming enough protein after weight training is essential to stimulate the growth and repair process which in turn works to build bigger and stronger muscles.
Protein and muscle growth go hand in hand
Also, studies have found that high protein diets can help to preserve lean body mass in both obese people and athletes when dieting, as well as improving overall body composition.
So how much does the government recommend we have?
According to the Australian Nutrient Reference Values (ANV), each day Australians should aim to consume 0.75/0.84g of protein per kilogram of body weight for both adult women/men respectively.
But what about those who are more active? Whether it be in team sports, endurance events or strength training, surely upping your level of physical activity would cause this intake to change?
Well, that’s what some new researchers were aiming to find out.
The ANV gives no variable for active or inactive individuals, which makes the RDI a very general recommendation and therefore not reliable for bodybuilders and strength athletes who generally have (and need) a higher intake of protein.
Past research doesn’t look at active individuals
In the past, studies have used the common nitrogen balance method to look at the minimal protein requirements needed rather than the amount needed for optimal muscle growth and immune function. This method is quite often how RDI’s are calculated.
The American College of Sports Medicine and the International Society of Sports Nutrition for example, recommend that active adults have between 1.2 and 2.0 grams of protein per kilogram of bodyweight per day, to boost recovery after training and to promote the growth and maintenance of lean muscle mass. However, these recommendations are based on studies that involve somewhat active or formerly untrained adults with normal amounts of lean body mass, not those who have been strength training or bodybuilding for quite some time.
Another issue with previous studies is the focus on the minimal protein requirements because athletes’ bodies can adapt to lower protein intakes over the adaption period of the testing. According to Examine.com, “nitrogen balance studies may show that people are in nitrogen balance at lower intakes of dietary protein because the body adapts to this lower amount by down regulating physiologically relevant pathways, like muscle protein synthesis and immune function.”
So, for strength athletes and bodybuilders who are wanting to maximise their muscle growth, they need to have a greater protein intake to ensure protein synthesis and immune function is at its best and not compromised due to a less than satisfactory intake.
Examine.com recently published an interesting report discussing a new study that looked at how much protein bodybuilders need for optimal muscle growth and immune function.
Eight healthy young men (average age of 22.5 years) from a university participated in this study. All men had at least three years of resistance training experience and were currently strength training four or more days per week with minimal aerobic exercise (less than 20 minutes per week).
Participants consumed 0.1 to 3.5 grams of protein per kilogram of body weight across several test days to determine their protein requirements. The tests were undertaken on non-training days, at least 48 hours after their last training session.
The findings from this study suggest that the daily protein requirement to cover the needs of experienced bodybuilders wanting to maximise muscle growth would fall between 1.2 and 2.2 grams of protein per kilogram of body weight per day, with the participants of the study averaging 1.7 grams per kilogram. From these findings, the authors conclude that almost all experienced bodybuilders would have their protein requirements satisfied by eating 2.2 grams of protein per kilogram of body weight.
2.2 grams of protein per kilogram of body weight will satisfy most experienced bodybuilders.
Although this study tested strength athletes training for around one hour 4+ days a week, the specifics of their training routine were not provided. So, it’s not known how training variables like frequency, intensity and volume influence protein requirements.
So, how much should we be having?
A daily intake between 1.4g and 2.2g of protein per kilogram of body weight appears to be ideal for active people with those athletes needing a higher percentage of muscle for their chosen sport needing more protein in their diet. Ie. bodybuilders require more protein than a marathon runners.
The study found the between 1.7 and 2.2g of protein per kilogram of body weight was adequate for muscle growth and good immune function in bodybuilders. So, see how you feel on different variations of protein intake.
What does this research tell us?
Well, it tells us that the RDI provided by the government for such a large and general group of people can obviously not be applied to all people with different levels of physical activity and muscle mass.
Those more active individuals, particularly those performing explosive muscle movements like bodybuilders or power-lifters, require a higher intake of protein in order to promote muscle recovery and growth than a marathon runner and much more than a sedentary adult.
Therefore, we can conclude that the RDI is not always an accurate source of dietary guidelines for athletes. The minimum daily protein requirement for an adult is enough to maintain protein levels, but not enough to encourage optimal muscle growth and repair for very active adults.
Bandegan, A., Courtney-Martin, G., Rafii, M., Pencharz, P. and Lemon, P., 2017. Indicator Amino Acid–Derived Estimate of Dietary Protein Requirement for Male Bodybuilders on a Nontraining Day Is Several-Fold Greater than the Current Recommended Dietary Allowance. The Journal of Nutrition, [online] 147(5), pp.850-857. Available at: Indicator Amino Acid–Derived Estimate of Dietary Protein Requirement for Male Bodybuilders on a Nontraining Day Is Several-Fold Greater than the Current Recommended Dietary Allowance..
Campbell, B., Kreider, R., Ziegenfuss, T., La Bounty, P., Roberts, M., Burke, D., Landis, J., Lopez, H. and Antonio, J., 2007. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, [online] 4(1), p.8. Available at: International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition.
Leaf, A., 2020. How Much Protein Do You Need Per Day?. [online] Examine.com. Available at: How Much Protein Do You Need Per Day?..
Patel, K., 2020. A Second Look At Protein Quantity After Exercise. [online] Examine.com. Available at: A Second Look At Protein Quantity After Exercise..
Nrv.gov.au. 2020. Protein | Nutrient Reference Values. [online] Available at: Protein | Nutrient Reference Values..
Thomas, D., Erdman, K. and Burke, L., 2016. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, [online] 48(3), pp.543-568. Available at: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise.