Bariatric Surgery

Bariatric surgery is a procedure performed on people with obesity to help them to lose weight. It is a weight loss surgery and its main mechanism of action is to reduce the number of calories the body consumes and/or absorbs by modifying the digestive system. Obesity is recognised as a disease because it reduces life expectancy and impairs bodily function. It has also long been linked to an increased risk of comorbidities such as:

• Death, from any cause
• High blood pressure (hypertension)
• High cholesterol (hyperlipidemia)
• High blood sugar (hyperglycaemia)
• Type 2 diabetes
• Cardiovascular heart disease
• Stroke
• Gallbladder disease
• Kidney disease
• Osteoarthritis
• Obstructive sleep apnea
• Fatty liver disease
• Cancer
• Mental illness like depression and anxiety
• Body pain and difficulty with physical functioning

Body-mass index (BMI) is a common measurement used to assess weight and nutritional status and the Ministry of Health (MOH) classifies obesity as having a BMI of over 27.5. The MOH’s clinical practice guidelines for obesity also state that bariatric surgery should only be offered as a treatment if the patient has class III obesity (BMI≥37.5) or class II obesity (BMI 32.5 to 37.4) with at least one comorbidity. Patients with class I obesity or lower (BMI <32.5) should not be offered surgery as routine practice regardless of comorbidities. Additionally, bariatric surgery candidates must be between 18 to 65 years old and for adolescents to qualify, various specialists must be consulted and the patient must reach an acceptable level of physiological bone maturity. Besides BMI, waist circumference (WC) is also used as an assessment of obesity in which having a WC of more than 90 cm in men or 80 cm in women is associated with a higher risk of cardiovascular disease.

As with any medical procedure, bariatric surgery carries risks. Besides the typical surgery risks like bleeding and infection, modification surgery on the digestive system additionally carries risks like gallstones, bile reflux, malnutrition, and dumping syndrome, a condition associated with nausea, abdominal cramping, and low blood sugar. Hence, bariatric surgery is only offered to severely obese patients that have been unsuccessful in other weight loss procedures such as exercise, medical nutrition therapy, lifestyle intervention, and counselling. Moreover, the surgery candidate must be willing to make permanent changes to their lifestyle post-surgery in order to maintain their weight. Bariatric surgery should therefore never be stigmatised as an easy-way out in weight loss. In fact, Class III obesity patients are considered to have extremely high risk of comorbidities and weight loss surgery is often necessary as a life-saving measure.

There are two mechanisms of bariatric surgery: restrictive and malabsorptive surgeries. Restrictive surgery involves physically restricting the size of the stomach and the amount of food it can hold, allowing the patient to feel full with smaller meals while malabsorptive surgery limits the amount of nutrients the body absorbs by bypassing portions of the small intestine. Bariatric surgeries are usually performed under general anaesthesia using laparoscopic surgery, which is less invasive compared to conventional open surgery and allows for a shorter recovery time.

Your bariatric team will continue monitoring your progress and your health post- surgery. You will likely work with a dietitian to decide what supplemental vitamins and minerals you need to account for malabsorption. Bariatric surgery is considered successful if 50% of excess weight is lost, and this occurs steadily over the first two years before plateauing or increasing. By all accounts, the success rate of surgery is relatively high at 90%.