There are a few theories out there, and the truth is probably a mixture of them along with some we don't know about. However, firstly, type 2 diabetes starts o

There are a few theories out there, and the truth is probably a mixture of them along with some we don't know about. However, firstly, type 2 diabetes starts out with no significant increase in blood glucose. The reason for this is that the body is very good at self-regulating (homeostasis), so it just produces a bit more insulin to keep glucose levels about right. This happens in the pre-diabetes stage. The insulin tells the fat cells to convert glucose into fat and store it, which causes people to put on weight. Type 2 diabetes should be viewed as a disease of too much insulin required, rather than too much glucose present. Yes, there ends up being too much glucose, but the primary problem is that you are giving the body too much energy to store, and it needs to produce too much insulin in order to do that. This leads into one reason for insulin resistance - the fat cells that are already full need a higher and higher level of insulin to persuade them to keep that energy stored there. Adding more insulin gets them to cram more in, but there is a limit to how much they can. Another possible reason for insulin resistance is constant high levels of insulin in the blood. Like a drug which you become resistant to if you are constantly taking it, your cells probably get resistant to the insulin. Insulin is secreted in response to high blood glucose and food intake. So there are two things that can cause a constant high level of insulin. The first is if fat cells are full, and they need a high insulin level to stop them dumping the stored energy back into the blood in the form of glucose. The second is if you're constantly snacking. For that reason, it is a real benefit to have a decent long stretch of the day when you don't eat anything. It used to be quite normal to have an evening meal at 6:30pm, and then not eat anything until breakfast the next morning, which gives the body a nice 12-ish-hour session each day of low insulin levels that allow resistance to recover. It's one reason why the 5-2 diet (where you eat normally for five days and then fast or severely diet for two days, every week) is successful.