i'd say you'd be much better off aiming for 150 than 50....but i'm guessing he did that as an easy catch-all to not get into all the nuance and calculations. so if you're trying to be more nuanced, run the 1.2/kg and do that. just in my comment i brought up multiple calculations, and that left out anything to do with sources of protein and specific amino acids, so likely in book didn't want to get too in depth on certain things.
bringing up bodybuilders and blue zones, lots of confounders there. your lifestyle and actions are likely no where close to theirs. still good as a data source though and think there is helpful info to impute there. do what you feel is best for you, but please make sure you are making those decisions on a good foundation of knowledge. probably veering away from your o.g. question, so i'd rec again if looking for a more nuanced protein discussion from attia listen to some of his podcasts focused on that, vs whats likely a chapter or few pages in book.
Yeah...no.
This is poor and dangerous advice. I don't often argue with people but it's important to understand why I'm against this advice.
The answer to one doctor saying something that is very different from every other doctor recommendation, nutritional study, government guidelines, and what is different from every known group of people on the planet who actually do live a long time, spread across the entire globe, is not to go and learn more about what that doctor is saying to try and understand his explanation of why he knows more than everyone else.
The answer is to question what that doctor is telling you and their reasoning behind what they're saying, because it could be incorrect.
His reasoning behind this is that protein is needed to maintain and preserve lean muscle mass (which is true), and that lean muscle mass and various strength studies and VO2 studies strongly correlate with longevity and lower all cause mortality rates (which is also true).
This does not imply that eating more protein will lead to lower mortality rates. In fact - there are several nutritional studies showing the exact opposite of this conclusion, that eating this amount of protein is going to lead to an early grave for most people. Not only this, but they show a dose dependent relationship which implies a causality. These studies are conveniently left out of the book.
However - there are (a few) other nutritional studies showing the opposite of this conclusion. That more protein is correlated with better health outcomes across the board.
This doesn't mean nutrition science is all nonsense or incorrect. It just means it's complicated and subject to misinterpretation.
There is a fundamental difference between these studies - which is what else you're eating with the protein. Either you're eating a lot of saturated fat and carcinogens, or you're eating a bunch of vitamins, minerals, polyphenols, and fiber. In other words, either you are eating protein from grain fed animals, or you are eating protein from plants.
Those studies he references citing fitness and mortality rates do not take nutrition into account at all. We have no idea how much protein those people were eating. All we know for sure is that they were very physically fit and active, which is strongly associated with all sorts of positive health outcomes, not just longevity.
His interpretation of the science is limited when it comes to nutrition.
He completely hand waves the entire field of nutritional science because he has various issues with all of the studies. Which is nonsense. Yes - there are a lot of problems with nutritional science, but most of those problems are related to how we are interpreting what the studies say, not a problem with the studies themselves.
An average Joe who reads this book and blindly follows this specific piece of advice will start eating down steak, chicken, and whey protein shakes and wind up dying an early death because they don't question things, because that's what your typical American thinks protein is.
Yes - eating protein is very beneficial. You should strive to eat a lot of protein. But it should come from a variety of plants, which have a lot of other useful compounds as well, or occasionally from low mercury content fish, which also have a lot of other useful nutrients (omega 3s, etc). If you want to eat more meat, it should be free range chicken, followed by the leanest cuts of grass fed beef. In general though - eat plants.
There is no direct scientific evidence that eating 1 gram of protein per pound of body weight will lead to a longer lifespan. None at all. No long term studies have been done to prove this theory in human beings.
Most studies on protein I have read don't even go that high, and it would be even more dangerous for a 200 pound man to follow the advice here, as they would be consuming 200 grams, or 800 calories of protein, per day. If this is coming from animal products it is coming with a lot of other things that are not strictly positive for your health. Especially if they are the modern day, grain fed animals with incredibly high omega 6 to omega 3 fatty acid profiles, which are associated with inflammation.
Different people do respond differently to different diets though, so the important thing is to try a diet and have your bloodwork done regularly, note how it makes you feel every day, and choose a diet that makes you feel great and has optimal bloodwork results for you.
There are a lot of other excellent parts of the book but this part about protein intake I don't think is sound advice, especially if someone views it out of context or assumes it applies to everyone.
Source:
https://pubmed.ncbi.nlm.nih.gov/32076944/
