Insulin resistance is not the same thing as diabetes, and does not inevitably lead to it. There is evidence that people who are overweight and insulin resistant, but do not have the genes for diabetes, will simply make more beta cells, and will successfully make more insulin to keep up with the insulin resistance. People with diabetes genes, conversely, seem to lose beta cell mass; there are some theories that at least one possible cause is that there’s a defect in the beta cells which, when they attempt to divide and thus create more cells as a normal person’s cells would do, the cells instead die, so that person ends up with fewer instead of more.
It’s not a bad idea to monitor your blood sugar, because obviously there are strong correlations, even if there’s not causation, between obesity and type 2 diabetes. Your doctor has probably looked at fasting glucose, but fasting glucose can still be okay for years after post-meal glucose starts to go out of bounds, so the post-meal numbers are the ones I’d look at. Get yourself a meter (Wal-Mart sells one, under the ReliOn brand, that’s $9 for the meter and $9 for a box of 20 test strips, and it’s about as reliable as the more expensive models), and eat something like a bagel (no cream cheese, or at least fat-free cream cheese, because fat slows down carb absorption), and then test your blood sugar at 1 hour and 2 hours after. A non-diabetic will register under 140mg/dL at 1 hour, and under 120 at 2 hours; if your numbers are slightly higher but close to that, I wouldn’t be terribly concerned, although I’d check it again in a few months, but if they’re significantly higher, then I’d go back to your doctor and insist on a glucose tolerance test.
To the extent your insulin resistance is caused by your weight (and excess weight can cause it, although it’s not the only cause), then losing the weight should significantly improve it. However, it’s really hard to lose the weight if your system is drenched in insulin all the time – one of insulin’s jobs is to move triglycerides into fat cells, and keep them there, so it’s difficult to get the fat to come out and be burned in a high-insulin environment. That’s where low-carb comes in; by keeping your carbs down and your protein moderate, you avoid calling for your pancreas to produce large amounts of insulin in the first place, and this makes it easier to mobilize the fat you’ve already got for energy. I would keep all carbs low, and get the carbs you do eat from things like leafy or cruciferous vegetables primarily, with a little bit of lower-carb fruits like berries and melon; the supposedly healthy complex carbs still break down to the simple sugars (glucose and fructose) before they’re metabolized, so they still require the same metabolic processes. Yes, you get more B vitamins and such from whole wheat bread than from Hostess cupcakes, but ultimately all the carbs in both turn into sugar, so you’re still going to cause significant issues with the bread; I would leave it alone until you get at least close to your goal weight – once you’ve lost the weight, you can be more liberal with your carbs, and adding back in carbs that are good sources of nutrients is better than adding back ones that aren’t.
I’m going to suggest some recommended reading and viewing. First, Jenny’s site, Blood Sugar 101, is great for bringing together the science about diabetes; you can see there that she lays out much of the information I conveyed above about how diabetes gets started. Second, Tom Naughton’s DVD documentary, “Fat Head,” is a great introduction to the science of low-carb, and entertaining besides. I also recommend Gary Taubes’ book, “Good Calories, Bad Calories” – it covers the science much more fully, although it’s a pretty dense read. And finally, I’ll recommend “Protein Power” by Drs. Michael and Mary Dan Eades; they lay out a low-carb eating plan, but they also talk a lot about the roles of insulin in the body, which I found really helpful.
Good luck to you!
