Obesity is becoming increasingly prevalent, and so is the number of people not responding adequately to conventional weight-loss regimens.  This is where bariatric surgery comes into the picture. Bariatric surgery is a surgery (usually involving the stomach) that’s performed to promote weight loss. Although considered risky over a decade ago, the safety of bariatric procedures has considerably improved in recent years.
When should you consider a bariatric procedure?
- A body mass index (BMI) of >35 kg/m2 in the presence of obesity-related complications such as type 2 diabetes mellitus (T2DM), obstructive sleep apnea, and cardiovascular complications.
- BMI > 40 kg/m2 irrespective of any complications.
- Have been evaluated by a medical team and are considered physically and psychologically fit to undergo the procedure. 
What are the types of procedures?
The most common bariatric procedures performed are sleeve gastrectomy, gastric bypass, and gastric banding.  The basic principle of these procedures is to reduce the effective stomach size so that food intake is considerably reduced, thereby leading to weight loss. The extent of weight loss differs from procedure to procedure and also depends on other factors like initial weight, etc. On average, research has shown that there may be 15-30% of weight loss that occurs in the long term, post-surgery. Yet, a loss of less than 20% weight post-surgery is considered to be a ‘surgical failure’ in some. 
What are the benefits of bariatric procedures?
Bariatric procedures have many benefits apart from weight loss, which is to significantly improve the quality of life and reduce mortality. There is some improvement to major improvement of other comorbid conditions in most people, and in a few, these conditions may be completely resolved. [1,2]
- Weight loss: It varies depending on the type of surgery and can be as high as 60% (or 15 BMI points) in the first year, but care should be taken as some of it may be regained in the long term.
- Dramatic reduction in obesity-related complications of diabetes, high blood pressure (hypertension), and high cholesterol (dyslipidemia) may be seen post-surgery.
- Most women experience a major reduction or complete resolution of polycystic ovarian disease (PCOD) after the procedure.
- Reduction of cardiovascular complications and risks thereof.
- A decrease in the risk of complications associated with diabetes.
- Risk of angina/heart attack cut in half.
- Potential decrease of anti-diabetes medications.
- Reduction of other complications of obesity such as acidity, obstructive sleep apnea, arthritis, asthma, impaired fertility, etc.
- Many people may also experience an improvement of mental and psychological health; for example, research has shown the resolution of depression in up to 55% of cases.
Are there complications of bariatric procedures?
Over the past decade, bariatric procedures have become considerably safer. Nevertheless, there is always a risk of some complications related to any surgery, and this applies to bariatric procedures as well.  These complications include the following:
- Nausea and vomiting
- Pain in the stomach
- Bleeding, infection or leakage at the surgical site.
A major complication is a malnutrition (specifically vitamin and mineral deficiencies). Because the stomach size is reduced, the absorption of certain vitamins and minerals may become impaired, which can be severe in some people and produce other issues. Vitamin D deficiency, for example, increases the risk of osteoporosis. In order to prevent this, a thorough nutritional counselling prior to the surgery and regular nutritional assessment may after the surgery may be needed in the first year. Lifelong vitamin and mineral supplements may also be needed. [1,3]
2. Dumping syndrome:
This is another complication seen post-bariatric surgery. In this condition, symptoms such as nausea, vomiting, sweating, tremors, loose stools, dizziness, or increased heart rate immediately after eating large quantities of food quickly, especially sweets and other forms of refined sugar are seen. 
3. Aesthetic complications:
Cosmetic or aesthetic problems can arise after the surgery when, for instance, a large amount of weight loss in a relatively short period of time can lead to excess skin, which often prompts people to undergo a cosmetic procedure to remove the skin flaps. Thinning of hair may also be occasionally seen. [1,2]
Although, overall, bariatric procedures today are quite safe to perform, especially if careful assessment and monitoring is done before and after the surgery, adopting a healthy lifestyle is just as important to continue to reap the benefits of the surgery.  A healthy diet and exercise routine is key to maintaining the weight loss and to control comorbid conditions like diabetes and hyperlipidemia post the surgery. It is also important to remember that no procedure is without complications, and some people may find it especially difficult to mentally cope with the changes after such surgeries. It is thus important that you talk to your doctor and surgery team to figure out if you meet the requirements in order to continue to be both physically and mentally healthy after the surgery.
- le Roux CW, Heneghan HM. Bariatric Surgery for Obesity. The Medical clinics of North America. 2018;102(1):165.
- Azagury DE, Morton JM. Bariatric surgery: Overview of procedures and outcomes. Endocrinology and Metabolism Clinics. 2016;45(3):647-56.
- Thibault R, Pichard C. Overview on nutritional issues in bariatric surgery. Current opinion in clinical nutrition and metabolic care. 2016;19(6):484-90.