Know About Bariatric Surgery

What to Know About Bariatric Surgery and Obesity

January 12, 2022

What to Know About Bariatric Surgery and Obesity: Obesity is a worldwide health problem that predisposes to several medical conditions. The co-morbid issues include heart disease, type 2 diabetes, high blood pressure, high cholesterol, sleep apnea, arthritis, infertility, and certain cancers. In the United States, the incidence of obesity is about 42% in the adult population[1], a growing number over the past several decades. Obesity accounts for over 400,000 deaths per year in the United States and is the second leading cause of preventable death after smoking[2].

Over 100 billion dollars are spent on the treatment of obesity and obesity-related medical conditions annually in this country.

The etiology of obesity is multifactorial, arising from both genetic and environmental factors. Common first-line treatment for obesity includes diet, exercise, pharmacology, and behavioral changes. However, studies show that the vast majority of patients regain all the lost weight within two years of beginning treatment[3].

Obesity is defined and classified by the body mass index (BMI), a calculation that is based on a person’s weight (kilograms) divided by the square of their height (meters). The BMI can reliably assess the amount of fat in a patient’s body and is used to screen for weight categories that are associated with certain medical conditions.

Class I obesity is defined by a BMI of 30-35 kg/m² and morbid obesity begins at a BMI above 35 kg/m². The goal of weight loss programs is to reduce the BMI to a healthy range of 18.5-25 kg/m², thereby decreasing the chances of developing obesity-related health conditions.

What to Know About Bariatric Surgery

Numerous studies have found bariatric (weight loss) surgery to be the most efficacious treatment for extraneous weight when performed in combination with diet, exercise, and healthy lifestyle changes. Bariatric surgery should be considered in patients with BMI >40 kg/m², or BMI>35 kg/m² with at least one obesity-associated medical comorbidity, according to the National Institute of Health consensus criteria for morbid obesity. Bariatric surgery has four main benefits when compared to non-surgical weight loss methods.

Four Main Benefits To Bariatric Surgery

First, weight loss surgery leads to a more significant reduction in weight when compared to non-surgical methods. After bariatric surgery, patients can achieve 60-70% total body weight loss, compared to an average of 10% with diet and exercise alone[4].

Second, the weight loss after bariatric surgery is sustained for up to ten years[5].

Next, significant weight loss after bariatric surgery leads to a reduction in several obesity-associated medical conditions, such as high blood pressure, type II diabetes, high cholesterol, sleep apnea, osteoarthritis, infertility, and certain cancers[6]. In fact, bariatric surgery has the potential to prevent, treat and oftentimes cure these conditions.

Finally, with these health benefits come improvements in overall mortality, such that lifespan has actually been shown to lengthen in those who underwent bariatric surgery for weight loss compared to those who did not[7].

Weight Loss Through Bariatric Surgery

What to know about bariatric surgery is that it achieves weight loss through a variety of mechanisms. Some procedures lead to a restriction in the amount of volume the stomach can hold, thereby decreasing the number of calories that can be consumed in one sitting.

Examples of this are the laparoscopic adjustable gastric banding and the laparoscopic sleeve gastrectomy. Other types of surgery produce malabsorption through a change in the intestinal anatomy and transit of food. This leads to a delay in the digestion and absorption of calories that are consumed through oral intake.

Examples include the laparoscopic Roux-en-Y gastric bypass and the duodenal switch. Finally, the hormonal component to surgical weight loss involves a hormone called ghrelin, which is responsible for signaling hunger to the brain. The circulating blood levels of ghrelin are reduced after surgery, thereby reducing the hunger sensation in those who have had surgery[8].

Obesity is a major public health concern globally and in the United States, and its effect on our population has been growing over the last several decades. It is a complex medical condition that is not fully understood and is associated with several other medical comorbidities.

Adequate treatment of obesity requires multimodal therapy, which may include dietary changes, increased physical activity, lifestyle modification, pharmacology, and bariatric surgery. Bariatric surgery should be considered for anyone with a BMI >40 kg/m², or BMI>35 kg/m² with other health problems, as it has proven to be the most successful method of achieving significant and long-term weight loss and reducing obesity-associated medical conditions.


  3. Curioni, CC. Long-term weight loss after diet and exercise: a systematic review. International Journal of Obesity 29, 1168-1174 (2005).
  4. Guraya, SY, ,Strate, T. Effectiveness of laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy for morbid obesity in achieving weight loss outcomes. International Journal of Surgery 70:35-43 (2019).
  5. Courcoulas AP, Belle SH, Neiberg RH, et al. Three-year outcomes of bariatric surgery vs lifestyle intervention for type 2 diabetes mellitus treatment: a randomized clinical trial. JAMA Surg. 2015;150(10):931–940.
  6. Mingrone G, Panunzi S, De Gaetano A, et al. Bariatric surgery versus conventional medical therapy for type 2 diabetes. N Engl J Med. 2012;366(17):1577–1585
  7. Sjostrom, L. Bariatric surgery and reduction in morbidity and mortality: experiences from the SOS study. Int J Obes. 2009;32.
  8. Ghrelin: a gut-brain hormone: effect of gastric bypass surgery. Geloneze B, Tambascia MA, Pilla VF, Geloneze SR et al. Obes Surg. 2003;13:17-22.
Know About Bariatric Surgery


Dena Arumugam, MD, is a board-certified general surgeon who specializes in minimally invasive surgery, general surgery and bariatric surgery. She earned her medical degree at the Albert Einstein College of Medicine and completed a general surgery residency at Rutgers Robert Wood Johnson Medical School. She refined her laparoscopic surgery skills at New York University Winthrop Hospital with fellowship training in advanced gastrointestinal and bariatric surgery, before returning to New Jersey to practice at Jersey Shore Advanced Surgical Associates.