The DS procedure is also known as biliopancreatic diversion. This is another kind of bariatric surgery, but it is not used as often, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Most surgeons won’t even consider it of the patient is not extremely obese with a BMI of 50 or higher. The procedure, which is one of the most complicated because it involves two separate surgeries, is also the most likely to cause complications and vitamins, minerals and protein deficiencies.