Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over 30 kg/m2; the range 25–30 kg/m2 is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.
Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, fatigue and unexplained weight loss. Symptoms may also include increased hunger, having a sensation of pins and needles, and sores (wounds) that do not heal. Often symptoms come on slowly. Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations. The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon.
Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat, or lean mass. Weight loss can either occur unintentionally because of malnourishment or an underlying disease, or from a conscious effort to improve an actual or perceived overweight or obese state. "Unexplained" weight loss that is not caused by reduction in calorific intake or increase in exercise is called cachexia and may be a symptom of a serious medical condition.
Gastric bypass surgery refers to a technique in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different gastric bypass procedures (GBP). Any GBP leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and physical response to food.
Bariatrics is the branch of medicine that deals with the causes, prevention, and treatment of obesity.
The duodenal switch (DS) procedure, gastric reduction duodenal switch (GRDS), is a weight loss surgery procedure that is composed of a restrictive and a malabsorptive aspect.
A laparoscopic adjustable gastric band, commonly called a lap-band, A band, or LAGB, is an inflatable silicone device placed around the top portion of the stomach to treat obesity, intended to decrease food consumption.
Sleeve gastrectomy or vertical sleeve gastrectomy, is a surgical weight-loss procedure, typically performed laparoscopically, in which approximately 75 - 85% of the stomach is removed, along the greater curvature, which leaves a cylindrical, or "sleeve"-shaped stomach the size of a banana. Weight loss is effected not only through the reduction of the organ's size, but by the removal of the portion of it that produces ghrelin, the hormone that stimulates appetite. Patients can lose 50-70 percent of excess weight over the course of the two years that follow the surgery. The procedure is irreversible, though in some uncommon cases, patients can regain the lost weight, via resumption of poor dietary habits, or dilation of the stomach over time, which can require gastric sleeve revision surgery to either repair the sleeve or convert it to another type of weight loss method that may produce better results, such as a gastric bypass or duodenal switch.
Metabolic dysfunction–associated steatotic liver disease (MASLD) is the name adopted in 2023 for the condition previously known as non-alcoholic fatty liver disease (NAFLD). This condition is diagnosed when there is excessive fat build-up in the liver, and at least one metabolic risk factor. When there is also moderate alcohol use, the term MetALD is used, and these are differentiated from alcoholic liver disease (ALD) when this is the sole cause of steatotic liver disease. The terms non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis have been used to describe different severities, the latter indicating the presence of further liver inflammation. NAFL is less dangerous than NASH and usually does not progress to it, but this progression may eventually lead to complications, such as cirrhosis, liver cancer, liver failure, and cardiovascular disease.
Bariatric surgery is a medical term for surgical procedures used to manage obesity and obesity-related conditions. Long term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size, reduction of nutrient absorption, or a combination of these. Standard of care procedures include Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch, from which weight loss is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point.
Management of obesity can include lifestyle changes, medications, or surgery. Although many studies have sought effective interventions, there is currently no evidence-based, well-defined, and efficient intervention to prevent obesity.
Bernhard Ludvik is a Specialist in Internal Medicine, board certified in Endocrinology and Metabolism. He is currently an Associate Professor of Medicine at the Medical University of Vienna. He serves as the Deputy Head of the Division of Endocrinology and Metabolism at the General Hospital Vienna.
Henry Buchwald is an Austrian-American surgeon and academic. He is the Professor of Surgery and Biomedical Engineering and the Owen and Sarah Davidson Wangensteen Chair in Experimental Surgery Emeritus at the University of Minnesota, Minneapolis, Minnesota.
SADI-S is a bariatric surgical technique to address metabolic disorders and to lose weight. It is a variation on the Duodenal Switch surgery, incorporating a vertical sleeve gastrectomy with a gastric bypass technique.
A duodenal-jejunal bypass liner, commonly called an EndoBarrier, is an implantable medical device in the form of a thin flexible 60 cm-long tube that creates a physical barrier between ingested food and the duodenum/proximal jejunum. The duodenal-jejunal bypass liner prevents the interaction of food with enzymes and hormones in the proximal intestine to treat type 2 diabetes and obesity. The duodenal-jejunal bypass liner is delivered endoscopically and has been tested on the morbidly obese as well as obese patients with a BMI less than 40, particularly those with difficult-to-manage type 2 diabetes. Despite a handful of serious adverse events such as gastrointestinal bleeding, abdominal pain, and device migration — all resolved with device removal — initial clinical trials have produced promising results in the treatment's ability to improve weight loss and glucose homeostasis outcomes.
Pradeep Kumar Chowbey is an Indian surgeon, known for laparoscopic and bariatric surgeries. He is the incumbent Executive vice chairman of the Max Healthcare, Chairman of the Minimal Access, Metabolic & Bariatric Surgery and Allied Surgical Specialities of the Max Healthcare Institute, New Delhi. He is the founder of the Minimal Access, Metabolic & Bariatric Surgery Centre at the Sir Ganga Ram Hospital, New Delhi and has served as the Honorary Surgeon to the President of India, Dalai Lama and the Indian Armed Forces (AFMS). The Government of India awarded him the fourth highest civilian honour of the Padma Shri in 2002.
Intestinal bypass is a bariatric surgery performed on patients with morbid obesity to create an irreversible weight loss, when implementing harsh restrictions on the diets have failed. Jejunocolic anastomosis was firstly employed. Nonetheless, it led to some unexpected complications such as severe electrolyte imbalance and liver failure. It was then modified to jejunoileal techniques. Viewed as a novel form of treatment for obesity, many intestinal bypass operations were carried out in the 1960s and 1980s. Significant weight loss was observed in patients, but this surgery also resulted in several complications, for instance, nutritional deficiencies and metabolic problems. Due to the presence of surgical alternatives and anti-obesity medications, intestinal bypass is now rarely used.
Garth Philip Davis is an American bariatric surgeon, physician, and author. Davis specializes in weight management and is known for his advocacy of plant-based nutrition.
Rachel Louise Batterham is a British physician who is a professor of Obesity, Diabetes and Endocrinology at University College London. She established the University College London Hospitals NHS Foundation Trust Bariatric Centre for Weight Management and Metabolic Surgery. She has extensively studied obesity, and has contributed to clinical management and the understanding of obesity-related diseases.
Edward Eaton Mason was an American surgeon, professor, and medical researcher who specialized in obesity surgery. He is known for developing restrictive gastric surgery for morbidly obese patients. Mason introduced the first gastric bypass surgery in 1966 and was the inventor of the first vertical banded gastroplasty surgery in 1980.
