Subnostr

the 6 hour figure is a reference to the fact that there is a "refractory period" associated with muscle protein synthesis ( MPS )

that is to say a high protein meal ( Leucine Amino Acid in particular ) will stimulate MPS for say 1.5-3 hours and then it cannot be stimulated again by a meal until about 6 hours pass. this is similar to how when you have an orgasm you can't have an orgasm again until some period of time passes.

the practical implication of this is that if you had a good meal and then had nothing to eat for the next 6 hours you haven't lost an OPPORTUNITY to build muscle because there was none. but if you continue to not consume protein after 6 hours you're now throwing away that opportunity to build more muscle.

this refractory period in evolutionary terms is probably related to the time it takes to digest something like a steak, but is not actually directly driven by digestion. the refractory period for MPS is AN INTERNAL CLOCK

think of it as Jet Lag. you fly to another time zone and the body ignores the sun rising / setting time and just uses an internal clock instead. same with refractory nature of MPS - the body ignores actual availability of amino acids from digestion of food and instead uses a clock to make assumptions about their availability so it builds muscle for 1.5-3 hours after a meal then stops and refuses to build again until 6 hours Post Prandium ( after a meal ).

it's actually hard to communicate what happens because our language is too primitive to explain how the body works. in the body most opposite processes run in parallel at all times. so you're both building and breaking down muscle 100% of the time and the same for fat etc. this isn't how people run their lives - nobody is running heating and AC at the same time for example, and for that reason our language is poorly equipped to deal with how the body works.

so when i say the body is building or breaking down muscle it can mean different things because the body is always doing both of those things and yet it doesn't always make sense to think in those terms and so on ... this is why people of average intelligence need rules of thumb and diets and so on because they can't understand how it actually works ...

Mike Dilger ☑️ 1y ago

Some processes always run at different rates, even opposite processes, but others approach being switched (e.g. insulin/ketosis) and the mental model of switching is accurate enough for practical purposes. It's even accurate enough for practical purposes for those processes that are much more smooth and not switchy (if you are correct enough about which process dominates).

What you've said is interesting about MPS. I didn't know these things.

There is a presumption there that I want to be building muscle. This is good advice for a bodybuilder, but not so much for my case, someone trying to stay alive for as long as possible. From what I understand, the smaller I am the better, including lean mass, modulo sarcopenia.

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Discussion

Dissident Sound 1y ago

the strongest causal relationship that i know of to longevity is visceral fat mass. the more fat you have inside your abdomen the shorter your life will be. this fat can be accurately measured using MRI and some clinics offer that service, but in most cases simply using a tape to measure your waist is good enough.

muscle mass ( and more importantly STRENGTH ) is positively correlated to longevity as far as i know, but i do NOT believe this relationship is causal. i believe that strength is a RESULT of health not the cause of it.

muscle mass can be beneficial because it is a calorie sink, but it isn't such a huge sink that it can't be easily overwhelmed with junk food.

Dissident Sound 1y ago

i never heard anybody say that having less muscle will make you live longer. it may be true but i never heard about it. i hope whoever studied this relationship has controlled for fat mass. that is a smaller person obviously will live longer than a bigger person but probably not because they have less muscle but because they eat less.

eating less does make you live longer. not only because you avoid diabetes but because your metabolism slows DRAMATICALLY when you eat less. my heart rate goes down by a THIRD when i diet. although we don't die from the heart mechanically wearing out it would be logical to assume that when metabolism slows damage accumulates slower.

so basically if you want to live as long as possible - eat less and keep your waist down to a small size.