Re: So, at what point
There's a difference between what someone perceives as a "taste" - and the effect of the chemical elsewhere in the body. Some potential sweeteners are sugar isomers. They have the same overall chemical composition but differ in the molecule's internal linkages. A chemical reaction can be dependent on the particular isomer form.
The human taste system is surprisingly non-specific - so can be fooled. A strawberry's sugar content is no different from many other fruits - but by evolution fools us into thinking it is sweeter.
Type 2 Diabetes appears to be a symptom for which there may be many different triggers. Genetics and obesity are major pre-dispositions. A recent study has said that even the 12% who have never been overweight - can possibly reverse the condition by losing 10% of their weight. This is attributed to a build-up of fat round certain organs.
Other trigger factors are irregular meal patterns, irregular sleep patterns, and stressful jobs.