I recently received the following question:
Supposedly I am "genetically doomed" to have diabetes even though my blood sugars have never quite gotten into the prediabetic range. However there has been a devastating death toll on both sides of the family from diabetes. What is your opinion of the book, [title of book deleted]?
Remember that part of the reason for publishing books is to make money, and part is to "spread the gospel." What percentage belongs to which part is sometimes difficult to decipher, although sometimes it’s clear that the author has no credentials and hence no credibility. On the other hand, some books, including those published by diabetes organizations such as the American Diabetes Association, can be assumed to represent mainstream thinking rather than off-the-walls nonsense.
If you have a strong family history of diabetes, then indeed you are at risk of getting diabetes someday. This raises the obvious question: can you offset the risk by changing what you eat or in other ways such as taking medications or potions? I could probably write a book myself about this, but will limit myself to this essay.
You indicate that your blood glucose (BG) levels have remained below prediabetic levels, which is good to hear. It’s now understood that there’s no sharp cutoff between normal levels and diabetes levels, and hence an intermediate category of blood glucose has been defined: someone with these in-between levels is described as having "prediabetes." Exact levels for normal vs. prediabetes vs. diabetes depend on whether you’ve eaten recently; if measured before the breakfast meal (which is called a FBG or sometimes a FPG), normal BG is up to 100 mg/dl (5.6 mmol/L), diabetes is 126 (7 mmol/L) or more, and prediabetes is anything in between (100-125 mg/dl, 5.6-6.9 mmol/L). BTW, if several FBG tests are done, and some are 126 or more, then I think most physicians would call the diagnosis diabetes even if others were normal or prediabetic.
(I must digress to discuss briefly an alternate definition for prediabetes that has fallen out of favor. The alternate definition is retrospective, and isn’t very useful: it defines anyone who has a diagnosis of diabetes as ipso facto having been prediabetic before they became diabetic.)
You should be aware that it’s possible for BG to occasionally go above normal, then return to normal: examples of when this might occur is during acute illness, treatment with certain medications (including steroids), or even after extremely large high-sugar-containing meals. Obviously, if you don’t check your BG during these special times, you won’t be aware that it’s been high. So my advice is to ask for a BG to be checked by the lab anytime your physician asks for blood to be obtained for testing for other reasons, and if you are have access to home glucose monitoring, to check during times of acute illness or after huge meals.