Public Health

What doctors wish patients knew about bariatric surgery

Sara Berg, MS , News Editor

AMA News Wire

What doctors wish patients knew about bariatric surgery

Sep 8, 2023

Obesity can result in the development of type 2 diabetes, heart disease and some cancers. A healthy diet and regular physical activity have often been the go-to for achieving and maintaining a healthy weight. But diet and exercise alone are often not enough to make lasting change. That is where metabolic and bariatric surgery can help.

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The AMA’s What Doctors Wish Patients Knew™ series provides physicians with a platform to share what they want patients to understand about today’s health care headlines.

For this installment, two obesity specialists took time to discuss what patients need to know about metabolic and bariatric surgery. These AMA member physicians are:

  • Ethan Lazarus, MD, a family and obesity medicine physician in Greenwood Village, Colorado, and represents the Obesity Medicine Association (OMA) in the AMA House of Delegates. He is also the past president of OMA.
  • Samer Mattar, MD, a bariatric surgeon and director of metabolic and bariatric surgery at Baylor St. Luke’s Medical Center in Houston. He is past president of the American Society for Metabolic and Bariatric Surgeons (ASMBS) and he is also an alternate delegate for ASMBS.

“Many patients think that by creating smaller stomachs—whether it’s with the sleeve or bypass—we’re actually limiting how much they can eat,” said Dr. Mattar. “That is true to a certain extent, but the way the operations work is that they reduce hunger.

“And what makes them so effective is that the patient’s appetite decreases dramatically. In fact, there are patients who forget to eat and wonder why they’re so tired,” he added. “So, the capacity for food is small, but the patients don’t mind because they’re not hungry. They have to be reminded to eat and this means that there’s less stress.”

“The problem with all the diets that we have is that they are associated with hunger and hunger is stressful, and any stress on the body changes our metabolism,” Dr. Mattar said.

One type of metabolic and bariatric surgery is the “gastric sleeve, where they take off the greater curvature of the stomach,” Dr. Lazarus said. “That part of the stomach is the part that makes a very potent hunger hormone called ghrelin.

“When they take off that part of the stomach, one of the main things that happens is your body stops telling you that it’s hungry,” he added. “It also shrinks the pouch where the food can go, so you can’t eat very much before you’re physically full and it provides immediate transit of the food into your small intestine, meaning you get an immediate bump in satisfaction hormones—you get less hungry, you get full quickly and your body tells you it’s satisfied.”

“The sustained weight loss for a sleeve is somewhere around 20% body weight loss, which is similar to the weight loss we are seeing with some of the new anti-obesity medications including those in development,” Dr. Lazarus said.

“The other procedure that’s commonly done is called a gastric bypass,” Dr. Lazarus said, noting “that’s basically a very short sleeve—about the size of a golf ball—plus they bypass a small part of the small intestine so you can’t absorb your food as efficiently.”

“The older surgical guideline said a person was a candidate for bariatric surgery if the BMI [body mass index] was 40 or if the BMI was above 35 with weight-related health problems,” Dr. Lazarus said. “The newer one that they published late last year says they should really be thinking about bariatric surgery for a BMI of 35 without diabetes, or 30 if the patient has diabetes.”

 “What we should be doing—since the AMA just passed policy de-emphasizing BMI—is we should be thinking about bariatric surgery for patients in whom the benefits outweigh the risks or in whom other modalities were not effective.” 

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For the best outcomes, “a day or two after we see a patient, they get prepared both mentally and physically for the operation,” Dr. Mattar said. “We evaluate them and optimize them over the course of two to three months until they’re ready for surgery to make sure that there are no surprises.”

Additionally, “sometimes we ask them to work with our dietitians and our physical therapists to lose a little bit of weight because we found that that improves the conduct of the operation,” he said.

This is “to make sure the patient is in a good mental state prior to doing the procedure,” Dr. Lazarus said. “If you have somebody with an eating disorder or untreated depression or alcohol-use disorder or things like that, the surgery can really go sideways. That can be a longer-term complication.”

“For example, developing alcohol-use disorder after the surgery. So, you really want to have a very good psychiatric assessment of patients before and monitoring after the surgery,” he said, noting “it’s not all physical. I’ve certainly seen patients develop, unfortunately, alcohol-use disorder after surgery, so we really want to be screening and monitoring for things like that.”

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 “We do all our operations either laparoscopically through keyhole surgery or robotically, so we don’t make big incisions anymore,” said Dr. Mattar.

“What this results in is markedly less pain. And when you have less pain, patients have the ability to get out of bed a lot faster. In fact, our patients get up and walk on the same day of surgery,” he said, noting that “when you walk, of course the circulation moves so you don’t get blood clots. The breathing is much better, so you don’t get pneumonia or chest infections, and you get out of the hospital quicker.”

“Now the length of stay after bariatric surgery is between one and two days where it used to be a week,” Dr. Mattar said. “All these factors have worked together to improve the overall outcomes and bariatric surgery has become as safe now as natural childbirth.”

“As you move into the surgical procedures, you’re thinking more in the range of a 20% to 30% weight loss,” Dr. Lazarus said, noting “we’re starting to see some overlap between the surgical procedures and the next generation anti-obesity medications.”

“In terms of weight loss, it happens pretty quickly after the procedure—with the most dramatic loss that first three or four months, continuing for one to two years,” he said. “In contrast, with oral medications, weight loss peaks at six to eight months, and up to 12 months for the injectables.”

“We don’t apply this to every patient, but we have come to realize that it’s very helpful to use anti-obesity medicines—especially the new ones that have come out—in combination with bariatric surgery,” Dr. Mattar said. Anti-obesity medications are used “either before surgery to help patients lose weight in preparation for surgery or after surgery if patients are finding that their weight is beginning to creep up again or they haven’t lost enough.”

“We sit with the patient, we analyze everything about their food and their activities, and if we find that they’re good candidates we will add medication in combination with the surgery,” he said, noting “we need all these different tools to use together to prevent the weight from recurring.”

“What we’ve noticed is, in terms of physiology or pathology, that the benefits are the immediate improvement in the chronic diseases that the patients came up to us with,” Dr. Mattar said. “For example, type 2 diabetes. We’ve seen patients who have been taken off their insulin even before they leave the hospital. It’s that quick.”

“Their diabetes, blood pressure and hypertension improves. Many of our patients come to us with three or four medications for blood pressure and as they lose weight and as they improve, we knock them off one at a time,” he said. “Their sleep apnea also improves. They get rid of their CPAP [continuous positive airway pressure] machines within a year and so on.”

“Patients have much more energy,” Dr. Mattar said, noting “at about four to six weeks, their energy goes through the roof. If you walk into a room, you can pretty much tell who’s had bariatric surgery because they’ll be sitting there restless, shaking their feet and trying to get up and wanting to do stuff.”

“And, of course, we find that a patient’s personality changes too. They tend to become more social, more positive and they have a lot more confidence,” he said. “It’s a spectrum of benefits from the operation.”

“Most people are going to need to continue to eat healthy, in part because their stomach just won’t tolerate a really big amount of food,” Dr. Lazarus said. “But also, some patients can have trouble digesting certain foods and can get dumping syndrome, wherein food gets dumped directly from the stomach into the small intestine without being digested. This can cause a group of symptoms, such as diarrhea, nausea and feeling light-headed or tired after a meal, that are caused by rapid gastric emptying.”

Bariatric surgery “almost forces patients to eat these healthier foods, but the stomach will fill up with a much smaller quantity and people need to be ready to do that,” he said.

“Exercise is very important, not only because it’s good for the heart and lungs, but many patients don’t realize that when they lose weight it’s never pure fat that they lose,” Dr. Mattar said, noting “it’s actually a mix of fat and muscle mass that is lost.”

“If left unchecked over the years, patients will find that they might have lost 100 or 200 pounds, but they’ve gotten progressively weaker,” he said. “And if that is maintained, then because the patient is weaker, then they’re not as active and they don’t burn as much.

“That is one of the factors that might cause weight recurrence, so we always tell patients they have to exercise once they’re about a month or so out of surgery,” Dr. Mattar said, adding that it is important to “exercise regularly and do a combination of aerobic and muscle strengthening exercises.”

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“Obesity is a mismatch between genetics and the environment. And although we’ve lowered their set point physically, we actually have not changed their genetics, nor have we changed their environment at all,” Dr. Lazarus said. “So, if the person’s having trouble in their environment because they’re working 50 hours a week and don’t have time for physical activity or sleep and we don’t work on that, well that’s still going to be a major driver of obesity.”

“That’s where intensive lifestyle intervention remains important for the person after bariatric surgery because it hasn’t changed the environment,” he said.

“Sometimes after surgery, this can cause friction in relationships. The wife lost 100 pounds but the husband's still heavy and he wants to keep eating. So, we need to keep an eye on that relationship,” he said. “There's even risk of separation and divorce after bariatric surgery.”

That’s why “we need to think about that whole family. We need to get the whole family on board and that the reason we’re doing this is to improve the quality of life and health,” he said, noting that “instead of talking about losing weight, we should be talking about getting healthy. It’s got such a nicer sound to it.”

“But we've got to get the whole family involved and we have to understand there can be cultural pieces of this,” Dr. Lazarus said.

“One of the drawbacks of bariatric surgery—because the stomach is smaller—is that if not appropriately monitored, patients can run into some nutritional, vitamin or mineral deficiencies,” Dr. Mattar said. “So, we ask all our patients to take vitamins and supplements for the rest of their lives.

“And every six months to a year, we check their levels. We do lab work to make sure that they’re not falling behind,” he added.

“Many—if not most—bariatric surgery programs never discharge a patient. We know that these patients need support, so we support them lifelong,” Dr. Mattar said. “We have a certain schedule that’s set up. We see patients every three months for the first year and then every six months thereafter.”

“The surgeons see the patients, the dietitians see the patients at certain intervals and if needed, we have psychologists also who see them because the patients go through many changes physically and mentally,” he said. “We also have a support group that meets every month.”

“It’s a standard required for accreditation that there be a monthly support group where patients can come together—both new and old patients—and share lessons learned with each other under moderation by a dietician, psychologist or physician,” Dr. Mattar said.

One misconception about bariatric surgery is that “it’s a cop-out. It’s not a cop-out. It’s not the easy way out,” Dr. Lazarus said. “People who have surgery still need to engage in physical activity, still need to engage in healthy eating, still need to work on stress in their life, still need to find time to sleep.”

“It’s an evidence-based treatment,” he said. “Nobody’s going to say that the knee replacement is a cop-out. That’s for a tough patient. It’s a tough procedure and they want to try to improve their quality of life.”

“So, I would compare bariatric surgery to a total knee replacement—it’s going to be for the more advanced patients with obesity where they’re going to get a lifespan benefit,” Dr. Lazarus said. “But the reason to do it is to make the person healthier so they can live a longer, better life with a better quality of life and spend less time seeing doctors for all the obesity comorbidities.”

“It’s just a tool that helps patients make changes that are more long lasting and more effective than were they to do them without the surgery,” Dr. Mattar said.