The study seems to be focused on diabetes so I don't know how closely it applies to bodybuilding. I'm not a scientist so I'm not going to try to understand or elaborate on it. There are plenty of science-minded people who can.
I'm a bodybuilder with years of real-world experience, years of posting physique pictures on this board that show my progress, and multiple posts on insulin use for bodybuilding that the majority of this board has found pretty informative and authoritative. I combine that with listening to more science-minded folks to enlighten my path and I've consistently heard that insulin is key to absorbing nutrients in massive caloric surpluses. I've seen that play out in my own journey as refining my insulin use (along with eating more, progressive overload training, etc.) the last few years has helped me continue to progress through previous all-time high weights.
Science can be a good guide but we can't completely rely on it when it comes to advanced bodybuilding that involves PEDs, extreme training, massive amounts of food, etc.
I think understanding the scientific mechanisms behind insulin's actions is interesting and relevant to us. It's also relevant considering what guys like Patrick Tuor claim. Tuor actually claims insulin doesn't really build any muscle and insulin using pros aren't any bigger than those who do! Milos is on the opposite end, and responds to this line of thought here, Holligsteads claims, obviously coming from Tuor:
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Many of these anti-insulin guys still say they use it but at small doses like 5iu. This, Milos says, is useless, you need supraphysiological amounts if you actually want to grow beyond normal.
So the question is, does extra insulin really push more nutrients into the muscle? Tuor says not really, it only does it "faster" or whatever. And that paper claims glucose uptake into muscle is not really reduced when insulin is withdrawn from a diabetic. Insulin does do things to tissues, so that's not the whole story, but is extra insulin really increasing nutrient
uptake by as much as we think?