This is a common misconception. Type 1 diabetes cases are more often acquired with no family history, there are some genetic associations but it is actually less strong than Type 2 (insulin resistance/diet related diabetes) where family history is a substantial risk factor. Pregnancy (gestational) diabetes isn’t just pregnancy related either as it is more likely in those with metabolic syndrome/obesity and is associated with type 2 as well, so it is also partially diet related.

> Not all diabetes is from sugar.

I would go further and just say no diabetes is “from sugar”, it’s just a completely uselessly simplistic way of looking at it (I know this was in response to GP comment). It’s not like low carb diets even prevent some people from getting type 2.

Type 2 diabetes is a disease of acquired insulin resistance for which excessive consumption of high glycemic index food (eg processed food with high sugar content) is a major risk factor, but not the only one.