“Obesity” specifically refers to an excessive amount of body fat. “Overweight” refers to an excessive amount of body weight that includes muscle, bone, fat, and water. Most health care professionals agree that men with more than 25 percent body fat and women with more than 30 percent body fat are considered obese. These numbers should not be confused with the body mass index (BMI), which is more commonly used by health care professionals to determine the effect of body weight on the risk for some diseases.

Obesity has reached epidemic proportions globally, with more than 1 billion adults overweight – at least 300 million of them clinically obese. In the U.S. , a majority of adults are overweight or obese, with more than 30 percent of adults considered obese (Body Mass Index, or BMI, greater than 30). An increasing number of adults are considered extremely obese (BMI greater than or equal to 40).

In recent years, obesity has emerged as one of the most serious medical conditions affecting the developed world and has become a major contributor to the global burden of chronic disease and disability. It is now the second-leading cause of preventable death in the U.S.

Obesity Overview

Obesity is a progressive disease that often contributes to serious health problems such as diabetes, high blood pressure, heart disease, sleep apnea, arthritis and even cancer. Individuals who are obese have a 10- to 50-percent increased risk of death from all causes, compared with healthy weight individuals (BMI 18.5 to 24.9). Most of the increased risk is due to cardiovascular causes. 3 Obesity is associated with about 112,000 excess deaths per year in the U.S. population relative to healthy weight individuals. 3
Being overweight or obese increase risk for: 6

  • diabetes
  • coronary heart disease
  • high blood cholesterol
  • stroke
  • hypertension
  • gallbladder disease
  • osteoarthritis (degeneration of cartilage and bone of joints)
  • sleep apnea and other breathing problems
  • some forms of cancer (breast, colorectal, endometrial, and kidney)

Obesity is also associated with: 6

  • complications of pregnancy
  • menstrual irregularities
  • hirsutism (presence of excess body and facial hair)
  • stress incontinence (urine leakage caused by weak pelvic floor muscles)
  • psychological disorders, such as depression
  • increased surgical risk
  • increased mortality

Body mass index (BMI), a ratio of weight to height, is one way to measure obesity. Health care professionals generally agree that people who have a BMI of 30 or greater can improve their health through weight loss. 1 This is especially true for people with a BMI of 40 or greater, who are considered extremely obese. 1

Preventing additional weight gain is recommended if you have a BMI between 25 and 29.9, unless you have other risk factors for obesity-related diseases. Obesity experts recommend you try to lose weight if you have two or more of the following:1
Family history of certain chronic diseases. H eart disease or diabetes
Preexisting medical conditions. High blood pressure, high LDL cholesterol levels, low HDL cholesterol levels, high triglycerides or high blood glucose
Large waist circumference. Men who have waist circumferences greater than 40 inches, and women who have waist circumferences greater than 35 inches 1

BMI is calculated by dividing a person’s weight in kilograms by height in meters squared. The mathematical formula is “weight (kg)/height (m²).” 7

Although weight gain is influenced by many social and psychological factors, at its most basic level, obesity can be described as an energy imbalance: People gain weight when they take in more energy (measured in calories) than they consume through physical activity and metabolism. Excess energy is stored as fat.

1. National Institute of Diabetes and Digestive and Kidney Diseases. Understanding Adult Obesity. https://www.win.niddk.nih.gov/publications/understanding.htm
2. World Health Organization (WHO). Obesity and overweight.
3. National Institute of Diabetes and Digestive and Kidney Diseases. Longitudinal Assessment of Bariatric Surgery (LABS). “Why did the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) launch LABS?” https://win.niddk.nih.gov/publications/labs.htm#whydid
4. Stein CJ, Colditz GA. The epidemic of obesity. J Clin Endocrinol Metab. 2004 Jun;89(6):2522-5. Review.
5. Johnson W, Demaria E. Surgical treatment of obesity. Curr Treat Options Gastroenterol. 2006 Apr;9(2):167-74.
6. National Cancer Institute. “Obesity and Cancer: Questions and Answers.” https://www.cancer.gov/cancertopics/factsheet/risk/obesity
7. Statistics Related to Overweight and Obesity. https://win.niddk.nih.gov/statistics/index.htm#preval

Weight Loss: Treatment Options

Treatment for obesity may focus on related health problems as much as on weight loss. Your physician can advise you on your various options for weight loss, which may include diet, exercise and lifestyle changes, as well as medication.

Numerous studies have shown that behavioral therapy to improve diet and physical activity can lead to weight loss of approximately 5 to 10 percent over 4 to 6 months.

When a person loses weight, obesity-related conditions such as high blood pressure and type 2 diabetes improve. But if a person regains weight, these benefits are lost. 1 In many cases, a person who regains weight ends up weighing more than he or she weighed before the intervention. 1

Doctors need effective weight-loss methods for people with extreme obesity and effective ways to maintain long-term weight loss. 1 Therefore, an increasingly common approach to weight loss is surgery. According to the American Society for Bariatric Surgery (ASBS), an estimated 220,000 people with morbid obesity in the U.S. will have bariatric surgery in 2008. This is up from more than 100,000 people in 2003 and from about 16,000 in the early 1990s.

In fact, bariatric surgery is the most effective way for people with extreme obesity to lose substantial weight and improve their weight-related health conditions, such as high blood pressure and type 2 diabetes. Studies show bariatric surgery resolves type 2 diabetes in 73% – 83% of patients; cuts the risk of developing coronary heart disease in half, is an effective treatment for obstructive sleep apnea and resolves the condition in more than 85% of patients. 2

Most bariatric (or weight loss) surgery focuses on either reducing the size of the stomach or reducing calorie absorption. Both approaches share the same goal: To reduce the body’s ability to absorb and store calories in the form of excess fat.

  • These procedures can have dramatic health benefits, such as improved control of blood sugar or even reversal of type 2 diabetes. However, any surgery, including bariatric surgery can carry serious risks for overweight patients, including death. 2
    You may be a candidate for surgery if you are an adult with:
    A body mass index (BMI) of 40 or more or a BMI between 35 and 39.9 and a serious obesity-related health problem such as type 2 diabetes, coronary heart disease, or severe sleep apnea (when breathing stops for short periods during sleep).
    Acceptable operative risks.
    An ability to participate in treatment and long-term follow-up.
    An understanding of the operation and the lifestyle changes you will need to make. 2

Additional treatment options for obesity other than surgery may be available and may be more appropriate for your particular medical condition. Always consult with your doctor about all treatment options, as well as their risks and benefits.

1. National Institute of Diabetes and Digestive and Kidney Diseases. Longitudinal Assessment of Bariatric Surgery (LABS). “Why did the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) launch LABS?” https://win.niddk.nih.gov/publications/labs.htm#whydid
2. American Society for Metabolic and Bariatric Surgery. Metabolic & Bariatric Surgery
Fact Sheet.
3. National Institute of Diabetes and Digestive and Kidney Diseases. Longitudinal Assessment of Bariatric Surgery (LABS). https://win.niddk.nih.gov/publications/labs.htm#howmany


Gastric Bypass Surgery

Surgical Weight Loss

The goal of weight loss surgery (bariatric surgery) is to reduce the body’s ability to absorb and store calories. This result is achieved by using either restrictive or malabsorptive bariatric procedures.

Restrictive procedures reduce the size of the stomach, limiting the volume of food that can be consumed at one time. Restrictive procedures include adjustable gastric banding (AGB) and Roux-en-Y gastric bypass (RYGB) – although gastric bypass is also malabsorptive as well.

Malabsorptive procedures reduce your body’s ability to store calories by diverting food away from the parts of your digestive system that absorb calories. Largely malabsorptive procedures include biliopancreatic diversion (BPD) and biliopancreatic diversion with duodenal switch (BPD-DS).

All these procedures are commonly used and have been proven effective for reversing or minimizing weight-related health problems.


Gastric Bypass Surgery

Gastric Bypass Surgery- Robotic surgery

Gastric Bypass Surgery- Robotic surgery

Gastric bypass is the most common bariatric surgery performed in the United States.1 It offers a combination of both restrictive and malabsorptive procedures, which appears to be a very effective recipe for weight loss. Moreover, it is considered the gold standard surgical treatment. 1

While gastric bypass has become fairly common, this elective surgery has serious risks. For example, potential early complications after gastric bypass can include bleeding, infection, leaks from the site where the intestines are sewn together, and blood clots in the legs that can progress to the lungs and heart.2 Surgeons must have excellent visualization, dexterity and control to complete this technically challenging operation successfully.

Bariatric surgery may be performed through “open” approaches, which make large abdominal incisions in the traditional manner, by conventional laparoscopy or laparoscopically with robotic-assistance ( da Vinci ® Surgery). With the laparoscopic approach, long-shafted instruments are inserted through tiny incisions and guided by a small camera that sends images to a television monitor. Most bariatric surgery today is performed laparoscopically because it requires a smaller cut, creates less tissue damage, leads to earlier discharges from the hospital, and has fewer complications, especially postoperative hernias. 4

While conventional laparoscopy is the most widely used approach for gastric bypass today, not all patients are considered candidates for traditional laparoscopy. Surgeons may determine that patients who are extremely obese, who have had previous abdominal surgery, or have complicating medical problems require a traditional open approach. 3 The da Vinci® System has been proven to help surgeons overcome these challenges with improved ergonomics, instrumentation and visualization.4, 5
Is surgery for you?

Bariatric surgery may be the next step for people who remain severely obese after trying nonsurgical approaches, especially if they have an obesity-related disease. Surgery to produce weight loss is a serious undertaking. Anyone thinking about undergoing this type of operation should understand what it involves. Answers to the following questions may help you decide whether weight-loss surgery is right for you.

Are you:
Unlikely to lose weight or keep it off over the long-term with nonsurgical measures?
Well informed about the surgical procedure and the effects of treatment?
Determined to lose weight and improve your health?
Aware of how your life may change after the operation (adjustment to the side effects of the operation, including the need to chew food well and inability to eat large meals)?
Aware of the potential risk for serious complications, dietary restrictions, and occasional failures?
Committed to lifelong healthy eating and physical activity habits, medical follow-up, and vitamin/mineral supplementation?

Remember: There are no guarantees for any method, including surgery, to produce and maintain weight loss. Success is possible only with maximum cooperation and commitment to behavioral change and medical follow-up—and you must maintain this cooperation and commitment for the rest of your life.

1. American Society for Metabolic and Bariatric Surgery. Metabolic & Bariatric Surgery
Fact Sheet.
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “ Open and Laparoscopic Bariatric Surgery.” Bariatric Surgery for Severe Obesity. https://win.niddk.nih.gov/publications/gastric.htm#complications
3. National Institute of Diabetes and Digestive and Kidney Diseases. Longitudinal Assessment of Bariatric Surgery (LABS). https://win.niddk.nih.gov/publications/labs.htm#whydid
4. Snyder BE, Wilson T, Scarborough T, Yu S, Wilson EB. Lowering gastrointestinal leak rates: a comparative analysis of robotic and laparoscopic gastric bypass.J Robotic Surg. 2008.
5. Jacobsen G, Berger R, Horgan S. The role of robotic surgery in morbid obesity. J Laparoendosc Adv Surg Tech A. 2003 Aug;13(4):279-83.
6. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Is Surgery for You?” Bariatric Surgery for Severe Obesity. https://win.niddk.nih.gov/publications/gastric.htm#issurgfor

da Vinci gastric bypass

If your doctor recommends surgery to control your weight, you may be a candidate for da Vinci Gastric Bypass, potentially the most effective and least invasive option for weight loss surgery. da Vinci Gastric Bypass allows your physician to provide the gold standard surgical treatment for weight loss using only a few small incisions.

da Vinci Gastric Bypass provides your surgeon numerous technical advantages — including improved ergonomics, better visualization and instrumentation. 2 These advantages may allow him or her to provide you a minimally invasive surgery even if you are extremely obese. da Vinci robotic-assisted laparoscopy has also proven to shorten procedures time and significantly reduce the risk of serious complications when compared to conventional laparoscopy.

Similar to conventional laparoscopy, da Vinci Gastric Bypass may also offer numerous potential benefits when compared with traditional open surgery, 3including:
Significantly less pain
Less blood loss
Less scarring
A shorter hospital stay
And a faster return to normal daily activities


As with any surgery, these benefits cannot be guaranteed, as surgery is both patient- and procedure-specific. While da Vinci® Gastric Bypass is considered safe and effective, it may not be appropriate for every individual. Always ask your doctor about all treatment options, as well as their risks and benefits.

While clinical studies support the effectiveness of the da Vinci® System when used in minimally invasive surgery, individual results may vary. Surgery with the da Vinci Surgical System may not be appropriate for every individual. Always ask your doctor about all treatment options, as well as their risks and benefits.