I heard that the weight-loss surgery can cure type 2 diabetes. Is that true?

Interesting question. Certainly many people with type 2 diabetes are overweight and losing weight improves glucose control. So yes, but now we know that type 2 diabetes is progressive with loss of pancreas function and loss of insulin so surgery wouldn’t help as you would need insulin. Timing might be considered critical. Remember all surgery has risks.

LD
Additional comments from Dr. Jim Lane:

It is now clear that type 2 diabetes results from peripheral insulin resistance and disordered insulin secretion. Obesity surgery is helpful in treating insulin resistance and improving cardiovascular risk. However, such surgery does not cure type 2 diabetes. Type 2 diabetes is a dynamic process with a changing plot line. Its outcome is often changed by previous exposure, control, and underlying genetics.

JTL