Though this would probably only result from abuse of HGH, not lower amounts?
https://academic.oup.com/jcem/article/88/4/1455/2845123"n conclusion, replacement therapy with a low-dose GH in GH-deficient adult subjects is
associated with a sustained deterioration of glucose metabolism as a consequence of the lipolytic effect of GH, resulting in enhanced oxidation of lipid substrates.
Also, a shift toward more insulin-resistant type II X fibers is seen in muscle. Glucose metabolism should be carefully monitored during long-term GH replacement therapy."
that study was done with therapeutic dosages and individuals who were actually deficient in GH.
http://diabetes.diabetesjournals.org/content/50/8/1891this one goes into the mechanisms as to how chronic GH exposure induces IR in the cells
I suspect, but can not demonstrate, that pharma has pulled a fast one on people again like they did with women and the estrogen-progestin therapies which ultimately lead to skyrocketing breast cancer rates. The fast one in this case, my belief is that HGH drugs being sold are fundamentally different to the actual growth hormone secreted in healthy youths. However, a simpler explanation might be that the method of administration results in synthetic GH administration behaving an in aberrant manner - having high activity in areas its not usually meant to. Again, this is only my suspicion, I cannot demonstrate this. But there has to be a reason naturally high GH production in youths doesn't result in worsening metabolic condition, but synthetic GH administration demonstrably does in adults.