As a T1D, I'll note that the GP didn't really comment on what it means to be a T2D. The characterization, however, is mostly true for an overwhelming majority of t2d, but completely false for t1d. T2D is controllable with diet and exercise alone in something like 80-90% of the T2D population. Weight and lifestyle factors make up an overwhelming percentage of the risk factors. And while there is clearly a genetic (usually associated with the likelihood that weight/lifestyle will give way to t2d, not that the genetics alone cause t2d) and medical condition component too, this is the clear minority.