> The amount of oil consumption is quite high. Every thing is fried or deep fried. You could easily see this in the snacks that are consumed with tea/coffee.

This isn't really accurate. It's is the common conception of Indian food based on what is usually available in the States, but that's usually only Punjabi food, and even for Punjabi food it's the sort of cuisine that you'd cater for a wedding. It's not at all representative of what people eat on a daily basis. It's like going to P.F. Chang's or Tex-mex and assuming that that's what people typically eat in China and Mexico (respectively).

Indian and Bangladeshi cuisines vary quite significantly by region, and in at least some cuisines there's very little oil and/or fried food.

Sure there is. However this article seems to make the point that just even if you eat right and are active, you are predisposed to these problems just by being of South Asian decent. The section of the article "The Indian/South Asian Risk Factor" talks about that.

From what I understoon, the section says:

  begun to unearth unique South Asian risk factors 
  that _may_ have genetic underpinnings

and gives example of one mutation.

The rest of "additional genetic and lifestyle-related risk factors" are primarily lifestyle or diet related.

It's not the oil, it's the carbs