Alright, going to tackle a big one today. Truthfully, the science behind the number is actually pretty sound. The issue is more with people seeing that number, thinking “i must need more than that,” and then doing whatever they think is right anyways. So here it is, some science to how much protein you should get!
Study 1 – Only the abstract is available by this link, but gives the number 1.7-2.2g/kg as a recommendation for an athlete. I should also say, if you have been going to the gym for 2+ years, and train 4+ times a week then I would call you an athlete! The study also suggests that closer to the 2.2g limit would be needed based on how much of an energy deficit diet you’re on.
Study 2 – “But I’m more of an athlete than 2+ years and 4+ times a week, I’m the gym warrior!” Don’t worry, even that case has some evidence for you. This second study looks at 8 men, aged 22.5 ± 1.7 y. I was definitely at my prime at that age, as are most! This study also used athletes weighing 83.9 ± 11.6 kg with various amounts of bodyfat 13.0% ± 6.3%. The study was very small, but used a new technology called “Indicator Amino Acid Oxidization,” that should be a very accurate answer.
What did they conclude? 1.7g/kg is the ideal number, and the %95 upper confidence limit is 2.2g/kg. This also means that the lower confidence limit is 1.2g/kg (but is not mentioned in the study.) So from Study 2 we can say that with %95 confidence that athletes need 1.2-2.2g/kg. But seeing as athletes never like the lower bounds of limits, lets just call it 1.7g-2.2g/kg is the ideal amount of protein for young athletic males. This also means weekend warriors, older athletes, or females will likely need less (probably not by too much) than this amount as well.
So there it is! IF you’re getting more than 2.2g/kg or 1g/lb of protein in your day, you’re just wasting your money…
I’d love to hear your thoughts on this!