>How long does this cure last until the unhealthy diet & lifestyle that originally caused the insulin resistance bring it back again?

Not Sarcasm:

1) We simply don't know. Effects seem durable while people take the drug, but we have limited long term data. We dont have large populations that have taken it for 10 or 20 years

2) When people go off GLP-1 drugs, about 50% of them bounce back to their original weight or gain more. about 50% of people hold steady or go on to lose more weight.

This demonstrates that individual behavior and actions play a critical role, even for people who have taken the drug.