There are many form but the general thin is that cells get resistant to massive amounts of insulin, which are caused by high blood sugars, resulting in higher b

There are many form but the general thin is that cells get resistant to massive amounts of insulin, which are caused by high blood sugars, resulting in higher blood sugars and/or higher insulin levels which can cause damage to any tissue. As far as I know (I have T1 diabetes, no doctor though) the Beta cells producing insulin have (like any cells) a sort-of define lifetime/production level and stressing them out doesn't help you in the long run. You can take medication to allow cells to have easier access to insulin, be more susceptible to it or increase the betacell insulin production but these are generally stopgap measures which in the end result in nearing Type 1 insulin levels if no change in lifestyle is taken. Many old people will get it (Type 2) anyway since the pancreas is simply out of juice, but with relatively simple medication it can be managed. Eating like a fat pig will definitely accelerate the reduction in betacell insulin production capacity and increase the insulin resistance of other cells as described above (nice feedback effect).