Historically, weight reduction operations have had a bad reputation, largely because the risks involved with two early procedures clearly outweighed any benefits.

The procedures have now been largely abandoned, according to Dr. Shah.

The jejuno-ileal bypass, which did not involve the stomach and as such was not a gastric bypass, was common in the 1970s and is responsible for much of the scepticism surrounding weight-loss surgery.

"That's because many patients who underwent this procedure developed kidney or liver disease, and some even died," said Dr. Shah. "For many patients, the risks of the operation clearly outweighed the benefits.

"As a result came the development of newer, safer, and superior operations and the procedure is no longer performed in the United States."

In addition the loop gastric bypass or Mini Gastric Bypass is also generally considered obsolete due to concerns about severe post-operative complications, such as leakage, ulcers, oesophageal cancer, and extreme patient discomfort.