Interesting coments, and question.
Now let me address this first.
YES! A person can develope periferal resistance to insulin, with the resultant of a wrong metabolism of glucose, and if not treated and or managed, might end up with AOD (adult onset diabetes)
Now, who is at risk?
The answer, overweight or obese patients, particulary with family history...nothing else and nothing more. Remember that the first line of treatment for a patient with AOD is diet, weight loss and excercise, before even thinking to start him or her on medication. Eating 5 or 6 times a day, healthy and balanced is the corner stone for the development of a weight managing diet, in other words that is the healthy way to go as far as eating during the day...not only for athletes, for everyone.
So I pretty much say that athletes, active people, with a healthy diet are far and away of getting this health problem.
Now, consuming gels and sport nutrients is a risk of developing problems in terms of glucose management. Well, so far evidence is inconclusive. Imagine then Lance Armstrong, this is a guy who uses so much gels and other sport nutrients...for example, he used 12 or 14 gels during his last marathon:eek: , and the guy as far as his glucose there are no reports of any problems(he has been doing this for years already). What I am trying to say is that because we use gels, bars, shots, blocks and so on, we are not particulary at higher risk for developing AOD that the rest of the population, in fact, in my opinion, we are at less risk.
Now there are plenty of info about diabetic athletes, who can actually benefit tremendously from excercise, even at pro level, with no problem, you can check this sites:
pubmed.com
medscape.com
nejm.com
There are very nice pieces of info, to read more about this topic, that for sure can eventually worry more than one.
Hope this helps a bit, and I would love to keep chatting about...
Best wishes

exercise increases insulin sensitivity as well

That is exactly right...the reason adipose tissue is prone to develope resistance to insuline, so the more adipose tissue, higher the risk of resistance to insuline, and or AOD. I f you add to the equation family history...then the things are even worse.

I'm no endocrinologist, however, from my study of huma physiology and biochemistry this is basically how it works:

Glucose cannot automatically enter a cell (unless it is a liver cell or a brain cell, but those are different story). In order to get glucose into a cell so it can be used for energy, insulin has to activate a recpetor on the outside of the cell and 'escort' glucose into the cell.

When a person has long-standing hyperglycemia (long-standing high blood sugar), the body begins to down-regulate the number of these receptors on the cell surface in order to prevent hte ceels from being inudates with too much glucose. This stage is what is happening when someone is "insulin-resistant"

However, too much sugar in the blood is a problem. When the glucose gets shut out of the cells, the pancreas gets the message that blood sugar is too high and more insulin is needed, so it steps up production. But then the person ends up with too much insulin that is ineffective at reducing blood sugar. Evenutally, the pancreas made give up making insulin entirely and the person may need insulin injections to get any glucose into the cells at all. This is why the terms "insulin-dependent" and "non-insulin dependent" are no longer used to describe Type I and Type II diabetest, because given a variety of factors, Type II diabetics can eventually end up needing insuling injections as well.

Now, if you are still reading after all that (bless you!) THE POINT IS the one time when insulin is NOT needed for glucose to be taken into the cells is DURING EXERCISE!!!! Because of the workload they are under, the cells take in glucose without the insulin escort. This is why exercise, along with diet, are the one of the most prescribed ways to control and prevent Type II diabetes (I'm not calling it AOD on purpose, because the forwing trend is for many kids, because of poor diet and lack of exercise to get this too!). In the diabetic, when exercising, blood sugar levels are being reduced despite the reduced number of insulin receptors. It is virtually a win-win.

So for these athletes who are sucking on carbohyradate gels all the time, as long as they are exercising and using the carbs they take in, they shouldn't be at any more risk then anyone else for developing Type II diabetes given constants of other predisposing factors like genetics, etc.

As a personal note, I like Clif bar prodcuts because they are organic and because they use brown rice syrup for the main source of carbs, which is lower glycemic index then the main ingredients in many other gels. And in another note. My father is a Type II diabetic- classic Syndrome X, obese, low activity level, cardiovascular disease, etc. With the new year he started running and walking. Since just the beginning of the year, he has lost 6 pounds and dropped his morning glucose readings from over 140 g/dL to 116 g/dL!!!!!!!!!!!!!!!!