Vertical sleeve gastrectomy (gastric sleeve) is the most common kind of weight reduction surgery now performed in the United States, followed by Roux-en-Y gastric bypass surgery, laparoscopic adjustable gastric banding (LAP-BAND or REALIZE Band), and biliopancreatic diversion with duodenal switch. In Europe, gastric bypass has become the most popular procedure used to treat obesity. The American Society for Bariatric Surgery estimates that about 150,000 people in the United States have had some form of weight reduction surgery. Almost all patients lose weight after surgery and about 80 percent achieve a weight less than what they started with. However, 50 years or more after their surgeries, many patients still experience abdominal pain, irritability, or other symptoms related to malnutrition. As with any major surgery, there is a risk of mortality associated with weight reduction surgery. Weight loss surgery prevents absorption of nutrients from food as much as 75% after gastric bypass surgery and 95% after vertical sleeve gastrectomy. This leaves the patient feeling hungry and unable to eat enough nutritious food to meet their body's needs. People who have had weight loss surgery may need special nutrition counseling after their surgery to learn how to choose foods that will help them maintain their weight after their operation. Over time, the stomach loses muscle tone and can't control its emptying process. Therefore, the patient is at risk for developing nutritional deficiencies post-surgery.