My support of lantus use in high cal/carb diets is almost irrelevant if GH.
If I’m not mistaken, the development of type 2 diabetes is a back and forth exchange of insulin resistance and overproduction of insulin from the pancreas compounding over and over.
Now maybe I’m a huge outlier here, and I certainly don’t have data on this, but I would be VERY surprised if the body could keep up with 700-1000g of carbs a day for long-ish periods without exhausting beta cells in the pancreas.
I’m a firm believer in food over compounds and have myself not gone above 6iu of GH. Gear also contributes here, and certainly metformin/berberine/telmisartan can assist with sensitivity, but I’d be shocked if the pancreas doesn’t have a limit.
First, I'll say that in your case you may be an outlier in the general population, but you absolutely represent highly competitive bodybuilders, and I feel that as this is a very important demographic here, so we cannot dispel with the fact that your carbohydrate intake is a model for people trying to grow.
With that being true: the development of type 2 diabetes is not so simple as you propose. Anyhow, what the user should be concerned with is the broad picture of insulin and early death.
The association between elevated endogenous circulations of insulin levels is tied to insulin resistance, yet the contribution of absolute or elevated insulin concentrations on the pathological course of progression to diabetes is something that may be inferred from various data.
Proposed natural history of T2D progression [14]
Note the correlation between insulin secretion (concentrations) and insulin sensitivity.
The mechanisms of insulin resistance involve impaired glucose transport via post-receptor defects in insulin signaling (i.e., GLUT-4 translocation; tyrosine kinase phosphorylation/signaling via the β-subunit of the IR)[14]: "Insulin resistance in most cases is believed to be manifest at the cellular level via post-receptor defects in insulin signalling... Possible mechanisms include down-regulation, deficiencies or genetic polymorphisms of tyrosine phosphorylation of the insulin receptor, IRS proteins or PIP-3 kinase, or may involve abnormalities of GLUT-4 function." [15]
(note that as mentioned in my prior post, insulin itself, as rhI, causes these post-receptor defects in insulin signaling through what is known as "insulin toxicity")
Very high plasma insulin levels are a predictor of the development of diabetes [14]. There are, further, independent risk factors (that the combined use of AAS aggravate substantially):
Independent risk factors for impaired insulin sensitivity:
1. central obesity
2. elevated triglycerides; ↓HDL, ↑Apo B, ↓Apo A1 (dyslipidemia)
3. endothelial dysfunction (altered arterial tone ⇒ atherosclerosis)
4. atherosclerosis (factors: platelet adhesion, aggregation, thrombogenecity ⇒ inflammation)
5. hypertension
6. prothrombotic activity
[14]
(as you are likely aware, androgens/AAS contribute to factors 2 through 6)
Rather than morbidity and type 2 diabetes progression being the simple consequence of insulin resistance/hyperglycemia & pancreatic secretion of insulin, there are multiple steps in the morbidity outcome, and high insulin concentrations are independently and consistently associated with early death.
I advise guys against year-round slin use and try to show them that it's not actually healthy.
I also strongly recommend reading this meta-analysis that even gives a dose-response for the cardiovascular harms of exogenous insulin and delves into the mechanistic aspects that largely apply to healthy adults as well as insulin-dependent diabetics: [19].
References:
[14] Cefalu, W. T. (2001). Insulin Resistance: Cellular and Clinical Concepts. Experimental Biology and Medicine, 226(1), 13–26. doi:10.1177/153537020122600103
[15] Wilcox G. Insulin and insulin resistance. Clin Biochem Rev. 2005;26(2):19-39.
[19] Herman, M. E., O’Keefe, J. H., Bell, D. S. H., & Schwartz, S. S. (2017). Insulin Therapy Increases Cardiovascular Risk in Type 2 Diabetes. Progress in Cardiovascular Diseases, 60(3), 422–434. doi:10.1016/j.pcad.2017.09.001