As per the World Health Organization (WHO), obesity is characterized by “excess or abnormal fat accumulation that presents a risk to health”. The Centers for Disease Control and Prevention (CDC) defines it as “weight that is considered higher than what is considered healthy for a given height is described as overweight or obesity”. Body mass index (BMI) is used in both to further define these categories; a BMI of 25 to 29.9 kg/m2 is regarded as overweight, while a BMI of 30 kg/m2 or higher is considered obese.

With a global prevalence of 890 million adults in 2022, according to WHO estimates, chronic obesity is an illness that has become more common in adults, adolescents, and children. It is currently regarded as a global epidemic. Though early screening of the high-risk population can provide means for counselling, early intervention in the form of medication, dietary and lifestyle modifications.

Obesity can be broadly categorized into three groups based on BMI; they are –

• Class I – 30.0 to 34.9 kg/m2
• Class II – 35.0 to 39.9 kg/m2
• Class III – ≥40 kg/m2

In accordance with NIH recommendations, the cutoff BMI also differs according to race and ethnicity, accounting for the Asian population. A BMI of more than 25 kg/m2 is considered obese. The concerning factor of obesity is not just the increase in weight in relation to height, but it is also linked to several potentially fatal consequences, including:

• Cardiovascular comorbidities- Obesity is associated with hypertension (high blood pressure), coronary artery disease (CAD), heart failure, and stroke.
• Endocrinology- Obesity can result in insulin resistance, which in turn brings in type 2 diabetes.
• Dyslipidaemia- Obesity raises the risk of cardiovascular illnesses by being linked to low levels of HDL (good cholesterol) and high levels of triglycerides and LDL (bad cholesterol).
• Respiratory disorders- Obesity is associated with sleep apnoea, asthma, and obesity hypoventilation syndrome (OHS).
• Gastrointestinal disorders- Obesity is associated with gastroesophageal reflux disease (GERD), and gallstones.
• Osteoarthritis- Being overweight puts strain on joints, especially the lower back, hips, and knees, hastening the deterioration of cartilage and causing osteoarthritis.
• Cancer– Many cancer forms are at risk due to obesity including breast, colorectal, endometrial, pancreatic, liver and oesophageal adenocarcinoma.
• Liver diseases- Obesity can cause Non-alcoholic fatty liver disease (NAFLD) by fat buildup in the liver, which can lead to cirrhosis.
• Psychological and Mental Health Disorders- Depression, anxiety, and binge-eating disorders common in obese people.
• Reproductive and Hormonal Disorders- Obesity is associated with polycystic ovary syndrome (PCOS), infertility, erectile dysfunction.
• Chronic Kidney Disease- Obesity plays a role in the development of renal disease, both directly, through injury to kidney tissues, and indirectly, by inducing or exacerbating illnesses such as diabetes and hypertension.

Obesity, Bariatric Surgery, and Who Qualifies

Keeping in mind the complications associated with obesity it is critical to control it. Therefore, in cases of extreme obesity, procedures such as bariatric surgery are opted.

Bariatric surgery: Bariatric surgery is primarily a medical technique intended to assist patients who have extreme obesity in losing weight when diet, exercise, and medication have failed to produce the desired results. Significant weight reduction results from the surgery’s alteration of the digestive tract, which lowers food intake and/or absorption. Candidates for surgery are people belonging to one of the categories:

• BMI (body mass index) more than 35.
• BMI exceeding 30 with a serious medical problem associated with obesity (including diabetes, severe joint pain, sleep apnea, and many more) that would improve with weight loss.
• Some racial groups, such as Indians and Southeast Asians, are more likely to be truncal obese and will therefore be affected by obesity at lower BMIs; as a result, these patients may be suitable for surgery at a lower BMI of 27.5 kg/m2. This might be relevant for patients who have immigrated to the US, but it might not be for their offspring.

It is important to note that bariatric surgeries are a set of different procedures that can range from restrictive, absorptive or a combination of both.

Restrictive procedures

Aims to minimize stomach capacity to restrict the quantity of food that can be eaten at once. Consuming fewer calories, aids in weight loss without significantly changing nutritional absorption, unlike other forms of bariatric surgery such as malabsorptive treatments. Adjustable gastric banding (Lap-Band) and gastric sleeve (sleeve gastrectomy) are common forms of restrictive bariatric surgery. Restrictive procedures are opted in patients that fit the following criteria;

• Restrictive operations can be advantageous for patients who require moderate weight loss, with their BMI being in the range of 30 to 39.9, since they do not significantly impact nutrient absorption.
• If a patient has relatively fewer or less severe obesity-related disorders, such as high blood pressure, sleep apnea, or joint discomfort.
• If the patients are expecting gradual weight loss, prefer less intricate procedures, desire a decreased chance of side effects, and are prepared to reduce weight more gradually.

Since a restrictive technique does not dramatically modify the digestive process, patients who are concerned about malnutrition or nutrient shortages may choose it.

Malabsorptive procedures

It is a kind of weight loss surgery that mainly functions by lessening the digestive system’s absorption of calories and nutrients. The majority of nutritional absorption takes place in the small intestine, which is partially bypassed to accomplish this. Malabsorptive procedures include biliopancreatic diversion (BPD) and jejunoileal bypass (JIB).

Combination of restrictive and malabsorptive procedures

Refers to a kind of weight reduction surgery that combines the use of stomach restriction (restrictive component) to control food intake and small intestine bypass (malabsorptive component) to lessen calorie and nutrient absorption. By limiting both the amount of food a patient may consume and the amount of nutrients their body can absorb from meals, this dual strategy aids in weight loss. The restrictive and malabsorptive procedures are Roux-en-Y gastric bypass (RYGB), BPD with duodenal switch (BPD/DS), and single anastomosis duodenal ileal bypass with sleeve gastrectomy (SADI-S) and one-anastomosis gastric bypass (OAGB).

It is important to note that bariatric surgeries are a set of different procedures that can range from restrictive, absorptive or a combination of both

Noha Hashmi, Final year medical student, Rak Medical and Health Science University

The indications for both malabsorptive and combination of restrictive and malabsorptive procedures are the same. Malabsorptive or combination operations are often more beneficial for individuals with a BMI of 40 or above because they result in quicker and significant weight loss.

Malabsorptive surgery is a more successful treatment than restrictive surgery alone if the patient has illnesses such as cardiovascular disease, severe sleep apnea, or uncontrolled type 2 diabetes, with a BMI of 35-39.9.  Diabetes remission or major improvements in blood sugar control have been known to result after procedures such the Roux-en-Y gastric bypass, with or without achieving weight loss.

Also Read: MoHAP trains school health staff to combat childhood obesity

Malabsorptive surgery may provide patients with extreme obesity or those who have not responded well to restrictive procedures the extra weight loss they require. Malabsorptive methods work better for those who need to reduce more weight quickly or who have a larger weight to decrease. Usually, 70–90% of the extra weight is lost after these surgeries, as opposed to 50–70% after restrictive treatments.

Patients who have a history of unsuccessful weight loss attempts or are at a higher risk of gaining the weight back may benefit more from a malabsorptive surgery, which produces more long-lasting, permanent outcomes.

Since malabsorptive operations decrease the body’s capacity to absorb vital vitamins and minerals, there is an increased risk of nutritional deficiencies. Individuals who elect these procedures must be prepared to get ongoing medical supervision and take lifetime vitamin and mineral supplements. Adherence to a strict diet that primarily focuses on high protein intake. One also needs to opt for routine blood testing to check for any deficits.

Before performing any procedure, a multidisciplinary team must be consulted. The multidisciplinary team for bariatric surgeries includes a bariatric surgeon, primary care physician, nutritionist, dietician, psychologist, psychiatrist, physical therapist, endocrinologist, gastroenterologist, anaesthesiologist and additional specialist like cardiologist, Pulmonologist and plastic surgeon if required.

Ultimately, the patient has complete control over whether or not to choose a beneficial procedure. Therefore, it is crucial that the medical practitioner fully informs the patient about the treatment, including all associated risks and its results.  After discussing the procedure, understanding patient expectations, and consulting the multidisciplinary team we can decide on a suitable management for the patient.