I just attended a workshop organized by the National Toxicology Program (part of NIH) called, "the role of environmental chemicals in the development of diabetes and obesity." There is a lot of evidence, and the evidence continues to grow, that exposure to various chemicals may contribute to the development of diabetes as well as cause weight gain and insulin resistance. Most of the evidence thus far is for type 2, but there are also studies on type 1 and gestational diabetes in relation to chemicals. We are *all* exposed to these chemicals-- many can stay in our bodies for years-- via food, air, water, products, dust, etc. This topic hasn't gotten a lot of press (yet), but the research is mostly very new. This evidence may help to explain a lot-- like why kids are getting type 2, thin people get type 2, rising rates of disease, etc. Diet and exercise play a role, but a study found that obesity did *not* increase the risk of diabetes in people with very low levels of chemicals in their bodies. This finding would imply that chemicals play a really important role in diabetes. There's a website here where you can read the NTP's review of the evidence: http://cerhr.niehs.nih.gov/evals/diabetesobesity/index.html I've also reviewed the evidence on my website, more for a lay audience: www.diabetesandenvironment.org, and see the "get involved" page to sign up for a listserve on this topic.