What is the safest form of weight loss surgery?

There are several different types of weight loss surgery, and each procedure has different benefits and disadvantages. Common forms of bariatric surgery include:
Gastric bypass (Roux-en-Y gastric bypass, or RYGB): Part of the stomach is closed off, leaving only a small pouch for food, which is connected to the middle part of the small intestine. Food can thus “bypass” a part of the stomach and small intestine. This procedure works the fastest and results in the greatest amount of weight loss, but it is the most risky of procedures.
Gastric sleeve (sleeve gastrectomy): A large portion of the stomach is removed, leaving a narrow tube, or “sleeve.” This procedure is safer than gastric bypass.
Duodenal switch surgery is a combination of a gastric sleeve and gastric bypass surgery.
Laparoscopic adjustable gastric band (lap-band): A soft silicone ring with an expandable balloon in the center is implanted around the top part of the stomach. It creates two compartments to the stomach, with a smaller part above the band so a person only eats enough to fill the top portion. This is often considered the least invasive procedure.
Gastric balloon: A type of balloon is inserted via the mouth into the stomach where it remains for up to 6 months, resulting in less space for food. It’s considered safe and does not involve any incisions, but it does not result in as much weight loss as the other options.