Well, Magirus did qualify it by saying "not always." Then came the ignorance.

My dad is "pre-diabetic", quite thin and fit, and has been watching his diet since a mild stroke 34 years ago. Mrs. Facie had gestational diabetes during both her pregnancies, despite no blood-sugar issues previously. My late uncle was diabetic, and wasn't "obese" or "sedentary" (he ran several miles a day).