Weight-Loss Surgery Glossary: Clearing up the Confusion

If you’re carrying enough weight to land you in the obesity zone—and nothing you try is helping you shed those pounds—there are options. One is weight loss surgery, which can be a tough decision and maybe even a scary one. But it’s good to know about what options you may have. There are a variety of weight loss procedures, or bariatric surgeries, that can change your stomach to limit the amount of food you can eat at one time. They also cut down on feelings of hunger, relieving your body from digesting large amounts of food. And they can all be done safely.

Although such support as medication, counseling, and other approaches may work well for some people, surgery is often the most effective approach for many with obesity, says, John Morton, MD, MPH, chief of Bariatric & Minimally Invasive Surgery for Yale Medicine. “Bariatric surgery is a tool that works,” says Dr. Morton.

Indeed, a growing body of evidence shows surgery can help people with obesity avoid, improve, and even reverse such conditions as diabetes, high cholesterol, high blood pressure, sleep apnea, and chronic pain. Dr. Morton reports that he sees this happen for patients all the time. “But it’s not just surgery alone—patients play a key role in the success of these operations,” he says. “In addition to agreeing to the surgery, they must commit to making important lifestyle changes in order to maintain a healthier weight. So, we always want to make sure they fully understand what weight loss surgery entails and what their experience could be like.”

Yale Medicine’s Weight Loss Program experts provided a glossary that explains all the different terms you may hear if you are exploring weight loss options.

Here are terms you might encounter if you are just starting to research weight loss surgery, or if you are planning to bring up the topic with your doctor.

Body Mass Index (BMI): An established measure that divides your weight (in kilograms) by your height (in meters squared). You can find BMI calculators for adults or teenagers online. To be a candidate for bariatric surgery, you must have a BMI of 40 or higher, or a BMI of 35 to 39 along with one or more medical conditions, such as diabetes, hypertension, or sleep apnea. Teenagers can have bariatric surgery if they have reached their adult height, are past puberty, and meet one of the qualifications listed above. This an important measure as life expectancy declines as BMI increases, says Dr. Morton.

Obesity: A medical condition in which a person has too much body fat for their height, increasing their chance of developing additional medical problems. Obesity is not just caused by eating too much; genetics is a contributing factor, as well as environmental, physiologic, and metabolic issues, and certain medications. A person has Class 1 obesity if they have a BMI of 30 to < 35, Class 2 if it is 35 to < 40, and Class 3 if it is 40 or more.

Overweight: When a person weighs more than is optimal for their height. Adults with a BMI of 25 to 30 are considered overweight. Overweight people have too much weight, some of which may come from fat, as well as water, bone, or muscle. “If you're overweight, you still have recourse,” Dr. Morton says. “It's still possible to take care of that with dieting.” Some people in this group, such as athletes, may have a lot of muscle weight, and therefore not as much fat, and will not necessarily have an increased risk of health problems due to their weight.

Waist size: Another measure of overweight and obesity that weight loss surgeons take into account. Generally, waist sizes greater than 35 inches in women and more than 40 inches in men put them at higher risk for type 2 diabetes and heart disease. People with "apple-shaped" bodies (a waist that is bigger than their hips) also have an increased risk for these conditions, which can occur at lower waist sizes for patients of Asian descent, says Dr. Morton. 

Metabolism: An umbrella term referring to all the chemical and physical processes in the body that convert or use energy. This includes the process of burning calories. Bariatric surgery can boost metabolism, which can lead to dramatic weight loss.

Hormones: Chemical messengers in the body that travel in the bloodstream to tissues and organs to control different activities such as growth, mood, and metabolism. Bariatric procedures often cause hormonal changes that, in turn, reduce hunger, increase satiety, and boost metabolism.

Co-morbidity: A medical condition that is simultaneously present with one or more other conditions. Obesity is considered a morbidity, and co-morbidities may help determine the course of a person’s treatment for their obesity. “The biggest ones we tend to encounter fall into the category of metabolic syndrome,” says bariatric surgeon Andrew Duffy, MD. “Metabolic syndrome is a constellation of insulin resistance, visceral adiposity, hypertension, and lipid abnormalities.”

Bariatric surgery: Another umbrella term, this time describing the category of procedures that work mainly by changing the anatomy and size of the stomach to limit the amount of food you take in, and, in some cases, altering the digestion process to improve fat metabolism. Some procedures impact the production of intestinal hormones that affect appetite.

Laparoscopic surgery: A minimally invasive surgery that involves making small incisions in the abdomen and inserting narrow tubes with long instruments attached. For patients, this approach means less pain and scarring, and a speedier recovery. While laparoscopic surgery is not optimal for every patient, over 99% of bariatric surgeries at Yale can be performed using this approach, says Dr. Morton.  

There are different types of weight loss surgeries, and it’s important to understand the pros and cons of each one based on your particular situation. Here we define some different weight loss surgeries and one endoscopic (nonsurgical) approach offered by Yale Medicine doctors.

Roux-en-Y gastric bypass: One of the most common bariatric surgeries, a minimally invasive procedure that creates a small, egg-sized stomach out of the regular-sized existing one, so patients will need less food to feel full. The procedure uses staples at the top of the stomach to create a pouch. Then, the pouch is attached to a surgically created Y-shaped section of the small intestine, so that the food bypasses the rest of the stomach. The result is fewer calories absorbed, plus changes in the hormones that regulate hunger and appetite.

Sleeve Gastrectomy: This is the most common procedure. The surgery removes about 80% of the stomach and staples together the remaining portions to create a thin, vertical, banana-sized sleeve. Similar to the Roux-en-Y gastric bypass, this sleeve holds less food, so you can eat less and still feel satisfied. This method also alters digestive hormones, reducing hunger. It’s a lower-risk procedure for those who would be at high risk for complications from other surgeries.

Revisional (redo) bariatric surgery: Revisional surgery can be done when a patient who has had a bariatric surgery has complications or fails to lose weight. A revision surgery may involve a procedure that’s different than the patient’s original weight loss surgery.

Endoscopic intragastric balloon: A nonsurgical approach that involves inserting a saline-filled silicone balloon that fills up about half of the stomach. (The balloon is inserted through the throat into the stomach while the patient is under sedation.) It increases the feeling of fullness after eating to limit the amount of food the patient consumes. The balloon is removed about six months later.

Good health is a lifelong endeavor and so is maintaining a healthy weight. Some of the most important work a bariatric surgery patient can do happens after recovery. Here we define common terms and phrases you might hear after you've had weight loss surgery.

Fluoroscopy imaging: A low-dose, continuous X-ray of the stomach area performed pre- and post-surgery using a contrast agent. Radiologists use this to check patients who undergo bariatric surgery to make sure there are no leaks in the stomach. Some may also have fluoroscopy imaging done before surgery. “Some patients might, for instance, be experiencing pain or reflux, which could be signs of hiatal hernia, and their physician or surgeon may refer them to us to take a look before being okayed for bariatric surgery,” says Steffen Huber, MD, a Yale Medicine radiologist.

Lifestyle changes: Weight loss from bariatric surgery depends on a lifelong commitment to diet and exercise, among other things. Bariatric surgery patients have to decrease the amount of food they eat, eat more protein-rich foods, and supplement their diets with vitamins and minerals. “Patients are partners in success with the surgeon, the nutritionist, and the exercise physiologist,” says bariatric surgeon Geoffrey Nadzam, MD. “There are life changes that occur that are wonderful, but that involves work on both sides of the operating room table.”

Body-contouring surgery: Surgery to remove excess skin and surrounding tissue after bariatric surgery. There are body-contouring surgeries that target different parts of the body (arms, breasts, face, thighs, abdomen). A surgeon may suggest having multiple body-contouring surgeries at the same time or undergoing them over a period of months or years. This type of surgery is done after a patient has reached a stable weight.

Dr. Morton encourages anyone who still has questions about weight loss, with or without surgery, to seek answers, and to keep watching their weight.

“Your BMI is probably the simplest screening tool out there,” he says. “Once you get to a BMI over 30, that's when things start to be concerning, because mortality rates start to rise. The good news is that there are several options available to you.”

Anyone who is concerned about their BMI shouldn’t hesitate to talk to their doctor, Dr. Morton adds.