Professor (USC) Dr Jörg Zehetner, a specialist in visceral surgery – upper GI and bariatric surgery as well as obesity surgery – has made a name for himself as an outstanding expert in the field of upper abdominal surgery. His specialist knowledge and experience cover all diseases of the esophagus and stomach, from cancer to reflux. Prof. Dr Zehetner is particularly distinguished by his outstanding expertise in the treatment of complex hiatal and abdominal wall hernias.
His medical career took him from Switzerland via Austria to the USA, where he worked as a professor at the renowned University of Southern California (USC). There, he received several awards for his outstanding teaching and is now an honorary member of the Society of Graduate Surgeons at USC in Los Angeles. Since returning to Switzerland in 2015, Prof. Dr Zehetner has worked as a specialist in surgery, with a focus on visceral surgery, at various clinics, including the renowned Beau-Site Clinic in Bern. As the founder of Swiss1Chirurgie AG, Prof. Dr Zehetner has established a leading center for obesity and reflux surgery, which ranks among the largest private practices in this field in Switzerland.
His expertise in laparoscopy and modern techniques such as robotic surgery make him a leading specialist across Europe, particularly in re-operations and complex cases. A key focus of his work is the treatment of gastro-esophageal reflux disease (GERD), for which Prof. Dr Zehetner employs the latest techniques. He is also an expert in the field of bariatric surgery. But what happens if patients regain weight despite having had surgery? The editorial team at Leading Medicine Guide wanted to find out more and spoke to Prof. Dr Zehetner.
Bariatric surgery, also known as obesity surgery or gastric bypass surgery, involves procedures designed to help severely overweight people lose weight and minimize associated health risks. These operations work by reducing the size of the stomach or rerouting the digestive tract, leading to a reduction in food intake or reduced nutrient absorption. Typical procedures include gastric bypass, sleeve gastrectomy and gastric banding. Bariatric surgery is generally considered a last resort for people with a body mass index (BMI) of over 40, or a BMI of over 35 combined with serious health problems caused by obesity. It can be an effective solution for weight loss, particularly when conventional methods such as diet and exercise have not been successful. However, it also happens that patients regain weight despite bariatric procedures such as gastric bypass or sleeve gastrectomy.
“Basically, it must first be noted that patients lose approximately 75% of their excess weight around 1.5 years after bariatric surgery. Take, for example, a man who is 1.80 m tall and weighs 150 kg. He is 75 kg overweight and, with a 75% weight loss, would have a target weight of 90–100 kg. People usually do not reach their ideal weight, but they come close and achieve this around 12–18 months after the operation. Over time, it is quite normal to put on 3–10 kilos again. If the weight gain is greater than this, one must consider whether further action is required in the form of revision surgery or drug therapy. It can be said that severely obese patients (weighing 150–200 kg) are at a higher risk of regaining weight. “That is why these patients often require a second operation involving malabsorptive measures, which allow parts of the small intestine to be bypassed by the food, so that fewer nutrients enter the body,” explains Prof. Dr Zehetner at the start of our conversation, and goes on to describe measures that should be taken before an operation:
“It is always advisable to lose a little weight (between 5–10 kilos, depending on the initial weight) before bariatric surgery, as this makes the operation safer and helps patients achieve better results post-surgery through increased motivation. Normally, around three months pass between the initial consultation and the operation. This is also stipulated by the Swiss Society for the Study of Morbid Obesity (SMOB; the leading Swiss society for research into obesity and metabolic disorders). During this period, the necessary investigations are carried out, such as gastroscopy and colonoscopy, abdominal ultrasound, heart and lung function tests, and a psychological assessment; nutritional counseling is provided, and a ketogenic diet (low in carbohydrates and high in protein) is prescribed three weeks before the operation. Post-operative follow-up appointments take place two weeks after the operation, then after six weeks, after three months, and subsequently annually. Every two years we perform a gastroscopy and, after 2–3 years, an abdominal ultrasound to check that everything is in order. Patients take vitamin supplements after the operation (primarily vitamins D and B, iron, calcium and magnesium).
“If the patient gains significant weight after the operation, in addition to further dietary advice, drug therapy may also be initiated, such as the GLP-1 weight-loss injection (this is for self-paying patients). Another option, which I also offer here in Bern, is a so-called ‘pouch revision’, also known as the Apollo procedure. In this procedure, the opening from the small stomach into the small intestine is narrowed endoscopically (this creates a pouch). This allows the patient’s weight to be corrected again. This pouch can also be reduced in size, for example ten years after the operation, if the small stomach pouch has expanded again. For this, a so-called Fobi ring (named after Dr Mal Fobi from the Center for Bariatric and Obesity Surgery in Carson, California), a small silicone ring, is placed slightly above the new junction between the stomach pouch and the intestine, preventing it from expanding and helping the patient to regain a healthy sense of fullness. The Fobi ring, a minimizer, remains in place permanently and exerts only very slight pressure when the patient wishes to eat, resulting in a quicker feeling of fullness. The procedure is performed laparoscopically and takes only about 30 minutes. “Here in Bern, we use the Fobi Ring in patients who are used to snacking frequently and need a greater sense of fullness right from their first operation,” explains Prof. Dr Zehetner.
Changes in eating behavior and lifestyle habits play a crucial role in the long-term success of bariatric surgery and in preventing weight regain.
After surgery, patients often experience changes in their appetite, feelings of fullness and sense of taste. This can lead to increased sensitivity to certain foods and raise the risk of overeating. To maintain healthy eating habits, it is important for patients to learn to listen to their body’s signals and focus on a balanced diet. This includes sticking to portion sizes, prioritizing protein-rich foods such as lean meat, fish, eggs and pulses, and avoiding foods high in sugar and fat, as well as liquid sources of calories such as fizzy drinks and juices.
Prof. Dr Zehetner explains: “Over a period of about 1.5 years, patients experience what is known as a ‘honeymoon phase’ because they feel less hungry and eat less, but do not suffer as a result. A small amount of food also remains in the stomach and does not pass straight into the small intestine. However, because some of it goes straight into the small intestine and does not remain in the stomach for long, GLP-1 hormones are released, which act in exactly the same way as weight-loss drugs and trigger a feeling of fullness in the brain. This effect may diminish over time as the body gets used to it, which can lead to old eating habits returning. If the patient then starts eating larger portions again, the Fobi ring described earlier can help. However, if the patient is one of those who increasingly crave sweet foods, it becomes a little more difficult to manage this, as sugar ‘slips through’. In such cases, supplementary dietary advice can help. Some patients require psychological support. This is particularly the case if they have processed trauma through overeating, or view food as a reward. Some patients compensate for their eating by consuming too much alcohol or smoking. It would be desirable if there were more psychologists in this field – there are simply too few in this area. Of course, we assess the patient’s habits before the operation. If a patient takes drugs, for example, we cannot operate on them – it is simply too dangerous, as the drug addiction could be exacerbated after the operation. And in the case of alcohol consumption, the amount must be limited, as you are no longer allowed to drink much alcohol after bariatric surgery because it is then absorbed more quickly and efficiently, as it goes straight into the small intestine. This can quickly lead to liver damage. Smokers should really not undergo surgery – we only perform sleeve gastrectomies on smokers. If a gastric bypass were to be performed, there is too great a risk of developing a stomach ulcer.”
Following bariatric surgery, hormone levels in the body can change, which may affect metabolism, feelings of hunger and satiety.
Hormonal changes can cause patients to regain weight after surgery, even if they adhere to dietary and behavioral guidelines. One hormone particularly associated with the regulation of appetite and body weight is ghrelin, also known as the hunger hormone. Ghrelin is mainly produced in the stomach and sends signals to the brain to signal hunger. Following bariatric surgery, ghrelin levels in the body may drop, meaning patients may feel less hungry. This initially contributes to weight loss. However, ghrelin levels may return to normal or even increase over time, which can lead to increased feelings of hunger and raises the risk of regaining weight. Another hormonal change that can occur following bariatric surgery involves peptide YY (PYY) and GLP-1 (glucagon-like peptide 1). These hormones are released in the gut after a meal and play a role in satiety and appetite regulation.
“There are essentially two groups of people who are at risk. On the one hand, there are smokers who gain weight when they stop smoking. And on the other hand, there are women going through the menopause. This is particularly distressing because these people gain weight even though they eat much less following bariatric surgery, yet still put on weight. Nutritional counseling or medication can help in such cases. However, we find that 80% of our patients are satisfied and lose weight successfully. We perform multiple operations on approximately 10–20% of patients, always keeping the patient’s health in mind. It must also be ensured that the patient genuinely wants to lose weight. If they do not, or do not cooperate properly, re-operation must be considered, as ultimately the patient can ‘outwit’ even a gastric bypass with a Fobi ring and still gain weight (for example, by eating salad dressings, ice cream, etc.),” notes Prof. Dr Zehetner.
Those who are only slightly overweight can do a lot themselves!
Prof. Dr Zehetner outlines the benefits of a ketogenic diet here: “If someone is 5–10 kilos overweight, they can manage this effectively with the right diet, motivation and exercise. The ketogenic diet is a good option here, as it largely avoids carbohydrates and sugar. It focuses on a protein-rich diet with fish, meat and eggs. Fructose, found in juices for example, is very counterproductive because it is immediately converted into fat in the liver. In any case, people who are slightly overweight (BMI between 25 and 35) can achieve a great deal through exercise and diet. Medication and GLP-1 weight-loss injections can also help. Today’s very high consumption of extremely sugary iced teas or energy drinks is particularly harmful. Unfortunately, consumption of these is high among young people. The many ready-made products on the market also generally contain cheap and therefore poor-quality ingredients. I can only urge people to avoid these. If an overweight person already has a BMI of 35, a conservative success rate is achieved in only around 2% of those affected. The other 98% will definitely need surgery.”
Aesthetics play a crucial role for many patients following bariatric surgery.
Following significant weight loss achieved through bariatric surgery, excess skin may remain, particularly in areas such as the abdomen, thighs, arms and chest. This excess skin can not only be aesthetically unsightly, but can also lead to functional impairments, such as skin irritation, infections or restricted mobility. The prospect of skin removal can be a strong motivator for many patients to achieve their weight loss goals and maintain healthy habits. The possibility of having excess skin removed can serve as a reward for their efforts and help to boost their self-esteem and satisfaction with their body.
Prof. Dr Zehetner comments: “Unfortunately, cosmetic surgery is usually paid for by the patient themselves. In Switzerland, this is very expensive and therefore a major problem for patients. However, if a flap of skin or an apron of fat is very large and can cause inflammation or skin irritation, then a health insurance provider may cover the costs. There is a lot of medical tourism here, but this is certainly risky. This is because it is often the case that while the operation itself goes well, the aftercare is not up to standard. In patients who are young and whose skin does not sag significantly to begin with, the skin may partially retract on its own. Bariatric surgery itself is not cosmetic surgery, but a metabolic procedure that leads to better health for the patient.
In good hands at the Beau-Site Clinic in Bern!
The Beau-Site Clinic stands out for its highly specialized medical expertise and is home to the two largest non-university centers in the Swiss Plateau: the Bern Heart Center and Beau-Site Visceral Surgery, alongside the Swiss1Chirurgie practice. Thanks to renowned specialists, state-of-the-art technology and personalized care, professional support is guaranteed. “Our clinic performs the most re-operations in the whole of Switzerland and also has the most experience in this area. We have already treated over 1,000 patients with anastomotic strictures. We also have the highest level of expertise in Switzerland with the Minimizer Ring and the Fobi Ring. We perform a total of around 400 bariatric surgeries per year,” notes Prof. Dr Zehetner, and with that we conclude our conversation.
Thank you very much, Professor Zehetner, for the excellent information!
