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Weight Loss Surgery / Metabolic Surgery / Bariatric Surgery 

What is Bariatric (Weight Loss) Surgery?


Bariatric surgery is surgery designed to cause long-term weight loss. This type of surgery has existed for about 50 years, and has tremendously evolved since the early days of “stomach stapling.” One of the most important innovations in the last decade has been the development of the laparoscopic approach. Most operations can now be performed laparoscopically, reducing the rate of complications, postoperative pain, and length of hospitalization.


Weight loss surgery is not a miracle; rather, it is a powerful tool to help you lose weight. In order to achieve the best results, one must also follow a healthy diet and participate in regular exercise. Surgery will help to restrict the amount of food that one takes in, but it has no effect on the number of calories burned. Successful weight loss surgery requires a lifelong commitment to healthy eating and exercise to keep the weight off.

Guggenheim Pavillion, Mount Sinai Hospital

How does Weight Loss Surgery work?


Bariatric surgery works by multiple mechanisms.

  1. Restriction. The operation reduces the size of the useable stomach, therefore one feels full quicker after a meal. Most operations reduce the stomach to the size of a small cup.

  2. Decreased absorption. The gastric bypass is an operation which "bypasses" a significant amount of the stomach and small intestine, causing a limitation in the number of calories absorbed from food.

  3. Hormonal effect. The bariatric operations alter the expression of hormones made in the body, particularly those made by the gastrointestinal tract. This can lead to an alteration in the feeling of hunger.  In addition, this hormonal effect is thought to also affect the regulation of metabolism in the body. This is thought to be why bariatric surgery has a profound effect on the resolution of Diabetes and High Blood Pressure.


In addition, Bariatric surgery has been shown to improve other obesity-related disorders such as obstructive sleep apnea, gastroesophageal reflux (GERD), and degenerative joint disease. In recent studies, patients undergoing bariatric surgery have also been shown to have improved survival over obese individuals not having surgery.


Weight loss surgery is not for everyone. The decision to undergo weight loss surgery is one of the biggest decisions you will ever make in your life. The decision should not be taken lightly. If you have not tried a formal, doctor-supervised dietary regimen, you should join an outpatient weight loss program, or consult with a registered dietitian or nutritionist, or discuss using medications to help you lose weight with your doctor.  If these approaches have failed, then weight loss surgery may be an option for you. Before making an appointment to see a surgeon specializing in weight loss surgery, you should discuss your weight loss options with your primary care doctor.


Patient Requirements:


Our program generally follows the criteria established by the National Institutes of Health. The criteria are: 

  • Age. You must be between 15 and 65 years of age. Those younger than 18 years of age and over the age of 65 must be considered on a case by case basis; they require a more thorough pre-operative evaluation.

  • Body Mass Index (BMI). (See below for more details) You must have a body mass index greater than 40, or greater than 35 with one or more weight-related health problems such as diabetes, hypertension (high blood pressure), high cholesterol or sleep apnea.

  • Unsuccessful previous weight loss attempts. You must have demonstrated an inability to lose weight through non-surgical methods.

  • Understanding. You must have a clear understanding of the surgery and its risks.

  • Cause of obesity. The obesity must not be caused by a correctable endocrine (hormonal) problem, such as hypothyroidism.

  • Commitment. You must participate in lifelong follow-up after weight loss surgery.

What is my Body Mass Index (BMI)?


Your body mass index, or BMI, is a number used by doctors as a yardstick to determine who is a candidate for weight loss surgery. If you know your weight in pounds and your height in inches, use the the link to this BMI calculator to compute your BMI:


  BMI Calculator  

Types of weight loss operations available:


Roux-en-Y Gastric Bypass


The gastric bypass is a restrictive procedure, but a small amount of malabsorption also occurs.  In a gastric bypass, the surgeon creates a 30 cc (1 ounce) gastric pouch from the upper part of the stomach. This is about the size of an egg. A relatively short intestinal bypass is then performed by bringing up the small intestine and connecting it to the small stomach pouch through a Y-shaped connection. As a result, patients eat less food, and somewhat less food is absorbed.

Sleeve Gastrectomy


In this operation, the stomach is cut into a long thin tube, or a "sleeve." This operation acts mainly by restricting the amount of calories ingested. In addition, since a large portion of the stomach is removed, it alters the expression of hormones in the gastrointestinal tract, leading to an earlier feeling of fullness.

Adjustable Gastric Banding (Lap BandTM)


In this operation, an adjustable silicone tube is placed around the "neck" of the stomach. When inflated, this tube constricts around the stomach and restricts the amount of food ingested. It is the simplest bariatric operation. The band is adjusted by accessing a device implanted underneath the skin of the abdomen to "inflate" or "deflate" the stomach.

Which operation is best for me?


Your surgeon will discuss the advantages and disadvantages of each operation and help you to decide which procedure is best for you. It is also helpful to have the support of a family member or friend as you are considering weight loss surgery. We encourage you to bring this person or persons with you to your initial consultation with your surgeon. Discussing your thoughts and feelings regarding the different types of surgery with this person may help you to make this decision more comfortably.


Weight Loss Surgery Consultations 

We also have several offices throughout Manhattan, Queens, and Brooklyn where we see patients for office consultations. All operations are performed at the Main Campus of Mount Sinai Medical Center in Manhattan.  However, we can typically arrange for preoperative and postoperative visits to be at these offices, and can coordinate appropriate consultations / tests locally in these neighborhoods also, for your convenience.



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