I had hoped to steer clear of this train wreck but now that there's some discussion of genetics I can't resist jumping in.
LAZ wrote:If you are not genetically predisposed, you will not develop diabetes. As Geralyn Spollett of the American Diabetes Association said, "You can’t just eat your way to Type 2 diabetes."
If you are genetically predisposed, you may develop diabetes even if you eat healthfully and are not overweight. Healthful diet and exercise reduce your risk, but do not eliminate it. Why some people with a family history of diabetes develop the disease and others do not is poorly understood.
Katie wrote:Thanks for this useful information, LAZ. (And here I thought this thread was irretrievable!) I may be the last person on Earth to learn this, but I did not know there was such a thing as a genetic predisposition to Type 2 diabetes -- specifically, that not just anybody could become diabetic.
The interplay of genetic and environmental factors responsible for type 2 diabetes (T2D) is highly complex so oversimplifications are unlikely to be correct or even useful (indeed misinformation may lead to harmful lifestyle decisions). This is a very active area of biomedical research and the final answers (if any exist) are not in. As someone with a background in mammalian genetics but no expertise in diabetes research, I'll go ahead and present a few of my own oversimplifications.
Marion Nestle, Professor of Nutrition at NYU
, has responded to Geralyn Spollet's statement, "You can’t just eat your way to Type 2 diabetes." Her reply in brief: "Wrong. You most definitely can eat your way to type 2 diabetes." I think a lot hinges on Spollet's use of the word "just'" and the fact she was quoted only very briefly in the New York Times article
. You can read Nestle's full response here
It's estimated that environmental and genetic factors contribute roughly equally to the incidence of T2D. A major environmental factor predisposing toward T2D is obesity caused by overeating and lack of exercise. No surprise there. But it's not just
Genetic factors also contribute significantly to diabetes risk*. But there's no scientific basis to divide people into two distinct groups, the "genetically predisposed" and "not genetically predisposed." Ongoing research indicates many genes contribute to T2D risk and each gene has a relatively small effect (over 20 genetic loci have so far been identified but the final number will probably be considerably higher). The outcome of this complex causality is that T2D risk is a continuum from high risk to low risk. Even those rare individuals with low risk combinations of genes will likely increase their probability of developing T2D if grossly overweight.
Even though diabetes is significantly influenced by one's genes, getting the disease or not is far from genetically preordained. Much is determined by choices made by the individual.* An excellent but highly technical review article on the genetics of diabetes can be found here: Doria, Patti and Kahn (2008) The emerging genetic architecture of type 2 diabetes. Cell Metab 8:186-200.