Surgery
This section is aimed at healthcare professionals
Bariatric surgery (or weight loss surgery) is the use of surgical interventions to treat obesity. As every surgical intervention may lead to complications, it is often regarded as a last resort when dietary modification and pharmacological treatment have proven to be unsuccessful.
Weight loss surgery relies on various principles; the most common approaches are reducing the volume of the stomach, producing an earlier sense of satiation (e.g. by adjustable gastric banding) while others also reduce the length of bowel that food will be in contact with, directly reducing absorption (gastric bypass surgery). Band surgery is reversible, while bowel shortening operations are not.
Almost all procedures can be performed laparoscopically. Complications from weight loss surgery are frequent. Early weight loss is faster after a bypass operation, however 3 - 5 years after surgery there is only a small (10%) difference in the amount of weight loss between lap banding and lap bypass surgery.
Two large studies have demonstrated a mortality benefit from bariatric surgery. A marked decrease in the risk of diabetes mellitus, cardiovascular disease and cancer has been found. Weight loss was most marked in the first few months after surgery, but the benefit was sustained in the longer term.
Table: The Appropriate Level of Intervention
| BMI Classification | Waist circumference | Comorbidities present | ||
| Low | High | Very high | ||
| Overweight 25-30 | ||||
| Obesity I 30-35 | ||||
| Obesity II 35-40 | ||||
| Obesity III >40 | ||||
| General advice on healthy weight and lifestyle | |
| Diet and physical activity | |
| Diet and physical activity; consider drugs | |
| Diet and physical activity; consider drugs; consider surgery |
Note that the level of intervention should be higher for patients with comorbidities regardless of their waist circumference. The approach should be adjusted as needed, depending on the patient's clinical need and potential to benefit from losing weight.
Although lifestyle modification, exercise, diet and medication can be effective at the earlier stages of overweight and class 1 obesity they are often less effective when class 2 or 3 obesity exists. Once a person's BMI exceeds 50 there is little evidence that these strategies are effective. In these situations Bariatric Surgery may be required. In addition, when established weight related illnesses are present there is a greater need for a level of weight loss that is unlikely to be achieved and maintained long term by non-surgical means.
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