The least invasive weight loss surgery is gastric bypass surgery which uses a smaller incision for the surgery than other weight loss surgeries.
There's also an endoscopic weight loss surgery procedure that can be done as well which is less invasive than other weight loss surgeries.
Weight Loss Surgery is pretty safe and most people who do have weight loss surgery come out of the weight loss surgery just fine.
However all surgery including weight loss surgery has some risks and weight loss surgery really only should be done if you're very sure you want the weight loss surgery done and other things such as exercise, eating healthy, etc haven't worked.
I have personally never heard of anyone dying as a result of weight loss surgery but I guess it could be possible especially if your health is not all that good before the surgery.
If you're overall healthy then the weight loss surgery should go just fine and the weight loss surgeon and doctors should discuss the risks associated with the weight loss surgery.
My sister went through weight loss surgery a few years ago and she did just fine and had no health issues.
Weight loss surgery can sometimes lead to Dumping syndrome, a condition that can lead to symptoms like nausea and dizziness and sometimes Low blood sugar.
But overall weight loss surgery when done by a trained surgeon which it should be done by is not very dangerous at all.