Obesity Primer for the Practicing Gastroenterologist

’ Stages of “ cally, obe- ux disease, fi fl www.amjgastro.com 17). Speci – cally, the model consists of 5 Harvard Medical School, Boston, 2 fi VOLUME 116 | MAY 2021 model (22,23). Speci ” 2 , 1 10% total weight loss (TWL) has been shown to reverse – OBESITY EVALUATION The obesity evaluationmedical, consists lifestyle, psychological, of and endoscopic several assessments. elements including Initial evaluation During the initial encounter,readiness physicians to should change assess their patients Change health behavior usingstages: the (i) precontemplation:consequences the individual of is theircontemplation: unaware the behavior individual of is and the awareopen resistant of the to to consequences and change, change, (ii) (iii) preparation: the individual shows OBESITY-RELATED GASTROINTESTINAL CONDITIONS Obesity is associated with several gastrointestinal (GI)including conditions various esophageal,hepatobiliary, gastric, and small pancreatic diseases intestinal, (14 colonic, sity may result inmore a severe clinical higher manifestations incidence, ofple, earlier these obesity presentation, diseases. increases the For and risk exam- of gastroesophageal re esophagitis, and esophageal adenocarcinoma by 2-,fold, 1.8-, and respectively 2.8- (18). Similarly,fatty the liver disease incidence is of approximatelycompared nonalcoholic 90% with in 25% patients in with thehas obesity, been general shown population to (19), hasten anddecompensated the obesity cirrhosis progression from (20). compensated However,7% to weight loss ofhistologic at features least ofobesity-related fatty GI conditions liver is summarized in (21). Table 1more A and can deeply be more explored in extensive thethese list work associations, of of gastroenterologists Camilleri should etsuspicion have al. (14). an and Given increased low thresholdpatient population. to In look addition, fortimely evaluation early these and diagnosis illnesses management of in maylence and help obesity this severity reduce and of the such preva- disorders. s Hospital, Boston, Massachusetts, USA; ’ s ff 88 34.9 . being – Tradi- 2 ” ), and class III 2 27kg/m 35 inches ( $ $ a chronic, relapsing, “ 25 and 39.9 kg/m – $ er from obesity (1). In the ff 25% in men and 35% in women 9). Finally, obesity may also be Christopher C. Thompson, MD, MSc. E-mail: [email protected]. and Christopher C. Thompson, MD, MSc ned as a body mass index (BMI) – ne and categorize obesity. Per the fi $ 2 , fi 1 102 cm) in men and 934. https://doi.org/10.14309/ajg.0000000000001200 . – cally, for patients with a BMI of 25 fi ) (5). The use of BMI, however, is limited 2 GASTROENTEROLOGY Correspondence: . It is further categorized into classI obesity (BMI 2 40 inches ( cially recognized obesity as a chronic disease (3). 40 kg/m ), class II obesity (BMI 35 $ ffi 2 $ neobesityinAsianandMiddleEastpopulations,re- © 2021 by The American College of Gastroenterology. Unauthorized reproduction of this article is prohibited. fi

,WCof 35% in women (depending on age) (4,10,11). Nevertheless, 2

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Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women The American Journal of Received June 4, 2020; accepted December 29, 2020; published online April 6, 2021 Massachusetts, USA. general gastroenterologist on the assessment andobesity. management of Tables containing high-yieldvided information for are quick reference. also pro- spectively, because of theirearlier higher appearance body of comorbidities fat (12,13). at a lower BMI and used to de 1 United States, the prevalence ismeeting even criteria higher for with obesity (2). 42.4% As of ofAssociation adults 2013, o the American Medical INTRODUCTION Obesity has become pandemic. It is estimatedmillion that adults more than (13% 650 worldwide) su Am J Gastroenterol 2021;116:918

Pichamol Jirapinyo, MD, MPH With worsening of the obesity pandemic, will gastroenterologists association see between obesity more and patients several with conditions gastrointestinal and this the chronic interplay between disease.gut obesity Given can hormones, pathophysiology and gastroenterologists play the an important role in the management of this disease. because Furthermore, patients more undergo bariatric surgery, an understanding of postsurgical anatomy and medicalbariatric and surgical endoscopic management complications is of essential. This article provides clinicalobesity tools for for the the general assessment Tables gastroenterologist. and containing high-yield management practical of reference. information are also provided for quick Obesity Primer for the Practicing Gastroenterologist 30 obesity (BMI kg/m in certain populations, such aspenic, the because elderly, it muscular, does andbody not sarco- fat distinguish between or lean(WC) its muscle may be and used. location Speci (6). Alternatively, waist circumference cm) in women suggestincreased central cardiometabolic risk obesity, (7 which is associated with Obesity Medicine Association, obesity is tionally, obesity has also been de of at least 30 kg/m multifactorial, and neurobehavioral disease, wherein an increase in body fat promotes adiposemass tissue dysfunction and physical abnormalmechanical, fat forces, and psychosocial resulting health consequences in (4). adverse metabolic, bio- de vary based on ethnicity, such as a BMI of with the healthy body21% fat ranging from 8%accurate to body 19% composition testing in can men beavailability. Furthermore, it and expensive is with important limited to note that these cuto REVIEW ARTICLE Copyright EIWARTICLE REVIEW 918

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precontemplation stage, the goal is to help move them to the Table 1. Gastrointestinal conditions associated with obesity contemplation stage before referral to bariatric specialists. Mo- tivational interviewing techniques, such as the 5 A’s (Ask, Advise, Gastrointestinal Gastrointestinal conditions Assess, Assist, and Arrange) and OARS (Open-ended questions, organ associated with obesity Affirmations, Reflections, and Summaries), can help with this Esophagus •Abnormal esophageal peristalsis process to elicit and strengthen patient’s motivation along this •Isolated hypertensive LES pressure spectrum (24,25). •Isolated hypotensive LES pressure •GERD •Erosive esophagitis Medical evaluation •Barrett’s esophagus A weight-focused history, physical examination, and laboratory •Esophageal adenocarcinoma evaluation should be obtained. Weights at specific time points, ff Stomach •Dyspepsia including around the major life events, and the e ectiveness of •Erosive gastritis previous weight loss attempts should be reviewed. Certain med- •Gastric ulcer ications can cause weight gain and should be downtitrated or REVIEW ARTICLE •Gastric cancer substituted with weight neutral drugs (Table 2) (26,27). On •Greater fasting gastric volume physical examination, BMI, WC, waist-hip ratio, and percent •Decreased satiation body fat should be measured. Signs of obesity-associated medical conditions including hyperpigmented skin around the neck or • Small intestine Duodenal ulcer axilla (acanthosis nigricans associated with insulin resistance), • Small intestinal bacterial overgrowth hirsutism (polycystic ovarian syndrome), large neck circumfer- • Diarrhea (related to changes in bile acids, ence (.17 inches for men or .16 inches for women suggesting accelerated colonic transit, and increased mucosal increased risk of sleep apnea), and thin, atrophic skin (Cushing permeability) disease) should be looked for (28). Baseline laboratory should • Increased absorption of glucose (related to increased include electrolytes, renal function, fasting glucose, hemoglobin SGLT-1) A1c (HbA1c), liver enzymes, complete blood count, lipid panel, • Increased absorption of protein (specifically whey thyroid-stimulating hormone, vitamin D, and urine albumin. hydrolysate) •Increased absorption of long chain fatty acids (related to increased induction of lipid binding proteins) Lifestyle evaluation Colon •Diverticulosis Dietary and eating habits should be reviewed using a 24-hour diet •Diverticular bleeding recall, food frequency questionnaire, or food log. Dietary habits •Recurrent diverticulitis including eating patterns (skipping breakfast, eating one large •Clostridium difficile infection meal per day, emotional eating, and grazing), frequency of eating •Adenomatous polyps out, and grocery shopping details should be evaluated. Further- •Sessile serrated polyps more, onset of satiation (the point at which one becomes full •Colorectal cancer ending one’s desire to eat during a single meal) and period of •Dyssynergic defecation satiety (the state of being full and satisfied which regulates the •Incomplete rectal evacuation time elapsed between 2 meals) should be assessed. •Fecal incontinence Physical lifestyle should be assessed. It is important to un- •Crohn’s disease (conflicting data) derstand whether patients have an active or sedentary lifestyle •Earlier loss of response to biologics in IBD patients and details regarding exercise (types, duration, and frequency). Liver •Nonalcoholic fatty liver disease Total energy expenditure (TEE) is the amount of calories burned per day. It is composed of resting energy expenditure (REE), •Nonalcoholic steatohepatitis thermic effect of meals (TEM), and energy expenditure from •Cirrhosis •Hepatocellular carcinoma physical activity (EEPA), which is further broken down into exercise and nonexercise activity thermogenesis (NEAT). Biliary •Cholelithiasis •Cholecystitis TEE ¼ REE ð60% 2 75%Þ 1 TEM ð10%Þ •Cholesterolosis 1 ½exercise 1 NEATð15% 2 30%Þ •Gallbladder cancer REE is the energy cost of physiological functions at rest, such Pancreas •Acute pancreatitis as respiration, cardiac output, and body temperature regulation. •Pancreatic cancer TEM is the energy required for digestion, absorption, and dis- GERD, gastroesophageal reflux disease; IBD, inflammatory bowel disease; LES, posal of ingested nutrients. Its magnitude depends on macro- lower esophageal sphincter; SGLT-1, sodium glucose linked transporter-1. nutrient composition with proteins requiring the most energy (20%–35% of energy consumed), followed by carbohydrates (5%–15%) and fats (5%–15%) (29,30). EEPA consists of exercise anticipation and willingness to change within the next 6 months, and NEAT, which is the energy expended for physical activity that (iv) action: the individual is in the process of changing their be- is not sleeping, eating, or exercise. As shown in the equation, havior, and (v) maintenance: the individual has sustained the new changing one’s lifestyle directly affects EEPA, resulting in changes behavior for more than 6 months. For patients in the in TEE and daily net calories.

Table 2. Medications associated with weight gain, weight neutrality, and weight loss

Medication type Weight gain Weight neutral Weight loss Antihypertensives Alpha-blockers ACE inhibitors, ARBs • Prazosin Beta-blockers • Doxazosin • Carvedilol • Terazosin Beta-blockers • Nebivolol • Atenolol Calcium channel blockers • Metoprolol Thiazides • Nadolol • Propranolol Antidiabetics Insulin, Meglitinides, Sulfonylureas, Alpha-glucosidase inhibitors, Bromocriptine, GLP-1 agonists, Metformin, Thiazolidinediones Colesevelam, DPP-4 inhibitors Pramlintide, SGLT2 inhibitors REVIEW ARTICLE Antidepressants MAOIs, Mirtazapine SSRIs SSRIs Bupropion • Citalopram • Fluoxetine • Paroxetine TCAs • Sertraline Antipsychotics Clozapine, Lithium Olanzapine, Aripiprazole, Lurasidone, Ziprasidone Quetiapine Risperidone Anticonvulsants Carbamazepine Gabapentin, Lamotrigine, Levetiracetam, Phenytoin Topiramate, Zonisamide Pregabalin, Valproic acid Contraceptives Progestin Barrier methods, Intrauterine device, Surgical sterilization Antihistamines First-generation antihistamines Second-generation antihistamines • Diphenhydramine • Cetirizine • Hydroxyzine • Loratidine • Meclizine Third-generation anti-histamines • Fexofenadine Alternative class of medications • Decongestants Steroids Glucocorticoids Inhaled steroids Topical steroids Alternative classes of medications • NSAIDs • DMARDs

ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blockers; DMARD, disease-modifying antirheumatic drug; DPP-4, dipeptidyl peptidase-4; GLP-1, glucagon-like peptide-1; MAOI, monoamine oxidase inhibitor; NSAID, nonsteroidal anti-inflammatory drug; SGLT2, sodium-glucose co-transporter 2; SSRI, selective serotonin reuptake inhibitor; TCA, tricyclic antidepressants.

Psychological evaluation procedure, one should note the presence of a hiatal hernia (Hill Grade Psychiatric history including anxiety, depression, and post-traumatic I–IV), esophagitis, Barrett’s esophagus, gastric polyps, gastritis, Hel- stress disorder should be assessed because this may translate into eating icobacter pylori infection, and malignancy. According the systematic disorders. It is important to assess whether patients suffer from bulimia review and meta-analysis conducted by the International Federation nervosa (recurrent episodes of binge eating 1 inappropriate com- for the Surgery of Obesity and Metabolic Disorders task force (63 pensatory behavior to prevent weight gain), binge eating disorder studies/22495 patients), abnormal esophagogastroduodenoscopy (recurrent episodes of binge eating without compensatory behavior), findings are likely to be found in at least 55.5% of patients before purging disorder (recurrent purging behavior without binge eating), bariatric surgery (25.3% for a subgroup of asymptomatic patients) and night eating syndrome (recurrent episodes of night eating) because with 16.5% having findings that led to modification or delay of the these require referral to a mental health specialist (31). Physicians may planned procedure and 0.2% having surgery cancelled (34). consider using the Eating Disorder Examination Questionnaire for Gastroenterologists should also be familiar with postbariatric sur- screening purposes (Table 3) (32,33). gical anatomy including normal and abnormal endoscopic findings. For Roux-en-Y gastric bypass (RYGB), the pouch and gastrojejunal Endoscopic evaluation anastomotic sizes should be assessed. The presence, location, and size of Endoscopy may be required as part of the initial evaluation for a marginal ulceration and gastrogastric fistula should be documented. subgroup of patients with obesity. In addition, for those who are For sleeve gastrectomy (SG), the sleeve dimension/configuration and undergoing bariatric surgery, the International Federation for the the presence of sleeve stenosis and/or angulation should be assessed. Surgery of Obesity and Metabolic Disorders recommends that a Furthermore, given the prevalence of de novo reflux (23%) after SG, preoperative esophagogastroduodenoscopy should be considered for gastroenterologists should be vigilant in assessing for the presence of all patients with and without GI symptoms (34). During this esophagitis (found in up to 53%) and Barrett’s esophagus (found in

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Eating Questionnaire Instructions: The following questions are concerned with the past 4 wk (28 d) only. Please read each question carefully. Please answer all of the questions. Please only choose one answer for each question.

01b h mrcnCleeo atoneooy nuhrzdrpouto fti ril sprohibited. is article this of reproduction Unauthorized Gastroenterology. of College American The by 2021 © Thank you. Questions 1 to 12: Please circle the appropriate number on the right. Remember that the questions only refer to the past 4 wk (28 d) only. On how many of the past 28 d … No days 1–5d 6–12 d 13–15 d 16–22 d 23–27 d Every day 1. Have you been deliberately trying to limit the amount of 012 3 4 5 6 food you eat to influence your shape or weight (whether or not you have succeeded)? 2. Have you gone for long periods of time (8 waking hours or 012 3 4 5 6 more) without eating anything at all in order to influence your shape or weight? 3. Have you tried to exclude from your diet and foods that 012 3 4 5 6 you like in order to influence your shape or weight (whether or not you have succeeded)? 4. Have you tried to follow definite rules regarding your 012 3 4 5 6 eating (e.g., a calorie limit) in order to influence your shape or weight (whether or not you have succeeded)? 5. Have you had a definite desire to have an empty stomach 012 3 4 5 6 with the aim of influencing your shape or weight? 6. Have you had a definite desire to have a totally flat 012 3 4 5 6 stomach? 7. Has thinking about food, eating or calories made it very 012 3 4 5 6 difficult to concentrate on things you are interested in (e.g., working, following a conversation, or reading)? 8. Has thinking about shape or weight made it very difficult 012 3 4 5 6

h mrcnJunlof Journal American The to concentrate on things you are interested in (e.g., working, following a conversation, or reading)? 9. Have you had a definite fear of losing control over eating? 0 1 2 3 4 5 6 10. Have you had a definite fear that you might gain weight? 0 1 2 3 4 5 6 11. Have you felt fat? 0 1 2 3 4 5 6 12. Have you had a strong desire to lose weight? 0 1 2 3 4 5 6

GASTROENTEROLOGY Questions 13 to 18: Please fill in the appropriate number in the boxes on the right. Remember that the questions only refer to the past 4 wk (28 d).Over the past 4 wk (28 d) … 13. Over the past 28 d, how many times have you eaten what other people would regard as an unusually large amount of food (given the circumstances)? ………………

14. On how many of these times did you have a sense of having lost control over your eating (at the time that you were eating)? ……………… Primer Obesity 15. Over the past 28 d, on how many DAYS have such episodes of overeating occurred (i.e., you have eaten an unusually large amount of food and have had a sense of ……………… loss of control at the time)? 16. Over the past 28 d, how many times have you made yourself sick (vomit) as a means of controlling your shape or weight? ……………… 921 REVIEW ARTICLE REVIEW ARTICLE 922 Copyright iaiy n Thompson and Jirapinyo h mrcnJunlof Journal American The Table 3. (continued)

17. Over the past 28 d, how many times have you taken laxatives as a means of controlling your shape or weight? ……………… 01b h mrcnCleeo atoneooy nuhrzdrpouto fti ril sprohibited. is article this of reproduction Unauthorized Gastroenterology. of College American The by 2021 © 18. Over the past 28 d, how many times have you exercised in a “driven” or “compulsive” way as a means of controlling your weight, shape or amount of fat, or to burn ……………… off calories? Questions 19 to 21: Please circle the appropriate number. Please note that for these questions the term “binge eating” means eating what others would regard as an unusually large amount of food for the GASTROENTEROLOGY circumstances, accompanied by a sense of having lost control over eating. 19. Over the past 28 d, on how many days No days 1–5d 6–12 d 13–15 d 16–22 d 23–27 d Every day have you eaten in secret (i.e. furtively)? 01234 5 6 … Do not count episodes of binge eating 20. On what proportion of the times that you have None of the A few of Less than half Half of the More than half Most of the time Every time eaten have you felt guilty (felt that you’ve done wrong) times the times because of its effect on your shape or weight?… times Do not count episodes of binge eating 012 3 4 5 6 21. Over the past 28 d, how concerned have you Not at all Slightly Moderately Markedly been about other people seeing you eat?… 012 3 4 5 6 Do not count episodes of binge eating Questions 22 to 28: Please circle the appropriate number on the right. Remember that the questions only refer to the past 4 wk (28 d). Over the past 28 d … Not at all Slightly Moderately Markedly 22. Has your weight influenced how you think about (judge) 0123456 yourself as a person? 23. Has your shape influenced how you think about (judge) 0123456 yourself as a person? 24. How much would it have upset you if you had been 0123456 asked to weigh yourself once a week (no more, or less, often) for the next four weeks? 25. How dissatisfied have you been with your weight? 0 1234 56 26. How dissatisfied have you been with your shape? 0 1234 56 27. How uncomfortable have you felt seeing your body (e.g, 0123456

OUE16|MY2021 MAY | 116 VOLUME seeing your shape in the mirror, in a shop window reflection, while undressing or taking a bath or shower)? 28. How uncomfortable have you felt about others seeing 0123456 your shape or figure (e.g., in communal changing rooms, when swimming, or wearing tight clothes)? What is your weight at present? (Please give your best estimate.) ……………………. What is your height? (Please give your best estimate.) ……………………. www.amjgastro.com If female: Over the past 3-to-4 mo have you missed any menstrual periods? ……………………. If so, how many? ……………………. Have you been taking the “pill”? ……………………. Obesity Primer 923

Table 4. Dietary interventions for weight loss

Dietary plans Description Energy focused Low calorie diet • 1,200–1,600 kcal/d Very low calorie diet • #800 kcal/d • Prescribed for #16 wk Protein-sparing modified fast • #800 kcal/d • High protein (1.5 g protein/kg ideal body weight) • Low carbohydrate (,20 g of carbohydrate per day) • Fat restricted to the protein source • Prescribed for #6mo

Meal replacement • Use of liquid shakes and/or bars with a known amount of energy and REVIEW ARTICLE macronutrient content to replace 1–3 meals Macronutrient focused Low carbohydrate diet • ,20% of total energy intake from carbohydrate Low dlycemic index diet • Replace high GI diet (GI $55) with low GI diet (GI ,55) Low fat diet • ,15%–20% of total energy intake from fat High protein • $20%–30% of total energy intake from protein Dietary pattern focused Atkins diet • Low carbohydrate (,20 g of carbohydrate per day; may increase to 50 g after 2 wk) • High protein • High fat Ketogenic diet • Low carbohydrate (,20 g of carbohydrate per day) • Moderate protein (10%–20% of total energy intake from protein) • High fat DASH diet • Complex carbohydrate • Lean protein (avoid red meat) • Low-fat dairy products as the primary source of fat • Emphasis on fruits and vegetables Mediterranean diet • Complex carbohydrate • Fish and poultry as the primary sources of protein (avoid red meat) • Olive oil as the primary source of fat • Emphasis on plant-based food (fruits, vegetables, grains, nuts, seeds) Ornish diet • Vegetarian Diet • Very low fat (,10% of total energy intake from fat) Paleolithic diet • Emphasis on fruits, vegetables, nuts, seeds, lean meat, fish • Avoid grains, legumes, dairy products, processed food Zone diet • 40% of total energy intake from carbohydrate • 30% of total energy intake from protein • 30% of total energy intake from fat Vegan diet • Exclusion of all animal products and byproducts Vegetarian diet • Exclusion of all animal products Dietary-timing focused Intermittent fasting • Fast every other day; no calorie restriction on non-fasting days Alternate-day fasting • 500 kcal/d on fasting days; no calorie Modified dlternate-day fasting restriction on non-fasting days 5:2 Intermittent fasting • For 5 d/wk, eat normally without calorie restriction Daily time-restricted feeding • For 2 d/wk, eat 500–600 kcal/d • 12–18 h of fasting per day; 6–12 h of feeding per day

Table 4. (continued)

Dietary plans Description Commercial weight loss programs HMR • Meal replacement 1 home delivered meals (low calorie diet) Healthy solutions plan • 1,200 kcal/d Decision-free plan • 3-2-5 daily plan (3 HMR shakes, 2 HMR entrees, 5 servings of fruits, vegetables) • 500–800 kcal/d • All shakes or 3-2 daily plan (3 HMR shakes, 2 HMR entrees) • Medically supervised Jenny Craig • Home delivered meals (low calorie diets) • Individual in-person or telephone-based counseling sessions REVIEW ARTICLE Nutrisystem • Home delivered meals (low calorie/low glycemic index diets) • 50% of total energy intake from carbohydrate • 25% of total energy intake from protein • 25% of total energy intake from fat SlimFast diet • Meal replacement 1 home delivered meals (low calorie diet) • 2 SlimFast meal replacements (shakes, bars, cookies) • One 500–600 kcal meal of one’s choice • Three 100 kcal snacks South beach diet • Home delivered meals (modified low carbohydrate diets) • ,50 g of carbohydrate per day (weight loss phase), then 75–100g of carbohydrate per day (maintenance phase) • Higher protein (25%–30% of total energy intake from protein) • Healthy fat Weight watchers • Points-based dietary system • Member is assigned daily and weekly points based on height, weight, age, gender • Food is assigned points based on calories, saturated fat, sugar (increased points), and protein (decreased points) • Zero-point foods: fruits, nonstarchy vegetables, eggs, skinless chicken, fish, beans, tofu, and plain yogurt • In-person meetings, web-based monitoring, or personal coaching calls

11.6%) in this patient population (34,35). For laparoscopic adjustable whereas men target 1,500–1,800 kcal/d (8). Alternatively, an indi- gastric band, retroflexion to evaluate for band erosion should be vidual’s energy requirement may be estimated using calorimetry or performed. available equations, and an energy deficit of 500–750 kcal/d or a 30% energy deficit can be prescribed. Alternatively, instead of a formal Other evaluation energy deficit target, lower calorie intake may be achieved by re- After the initial evaluation, additional studies, such as direct/indirect striction or elimination of particular food groups, such as carbohy- calorimetry, Homeostatic Model Assessment of Insulin Resistance, drates. According to the US Dietary Guidelines, the recommended liver ultrasound with elastography, and magnetic resonance elas- macronutrient proportions consist of carbohydrate (45%–65%), tography, may be obtained on a case-by-case basis. Furthermore, protein (10%–35%), and fat (20%–35%) (36). Adjusting these pro- referral to appropriate specialists for signs or symptoms of non-GI portions may facilitate weight loss in some individuals by simplifying obesity-related comorbidities should be considered. dietary goals. Although there are no universally accepted definitions, examples of macronutrient-focused diet plans include high protein OBESITY MANAGEMENT ($20%–30% protein), low carbohydrate (,20% carbohydrate), and The spectrum of obesity treatment options includes lifestyle low fat (,15%–20% fat) diets (37–40). There are several randomized, modification, pharmacotherapy, endoscopy, and surgery. controlled trials comparing diets with various macronutrient compositions. The largest study conducted by Sacks et al. randomized 811 Lifestyle modification overweight adults to 1 of 4 diets—low fat/average protein (highest Lifestyle modification (LM) is considered first-line therapy for the carbohydrate: 65% of calories), low fat/high protein, high fat/average treatment of obesity. It includes 3 primary components—diet, exercise, protein, and high fat/high protein (lowest carbohydrate: 35% of cal- and behavioral therapy. ories). No significant differences in weight loss were observed among To achieve weight loss, an energy deficit is required. This can be the 4 groups at 2 years (41). Other trials also demonstrated similar accomplished by restricting caloric intake or limiting certain food types. results with meta-analyses showing that adherence is the strongest To reduce caloric intake, women should target 1,200–1,500 kcal/d, predictor for weight loss (42). Macronutrient content may affect

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Medications Dosage/titration Mechanisms of action Efficacy Contraindications Common side effects FDA status Phentermine (Adipex) 15 mg qd (starting dose) Norepinephrine-releasing 6.8% TWL at 28 wk (96) Pregnancy/breastfeeding Headache, elevated BP, Approved in 1960s for short- 01b h mrcnCleeo atoneooy nuhrzdrpouto fti ril sprohibited. is article this of reproduction Unauthorized Gastroenterology. of College American The by 2021 © 37.5 mg qd agent History of CVD elevated HR, palpitations, term use (3 mo) MAOIs (within 14 d) insomnia, dry mouth, Hyperthyroidism constipation, anxiety Glaucoma History of drug abuse Orlistat (Xenical) 120 mg tid before meals Pancreatic and gastric lipase 7.4% TWL at 1 yr (97) Pregnancy Decreased absorption of fat- Approved in 1999 for chronic Alli (OTC) 60 mg tid before meals (for inhibitor Chronic malabsorption soluble vitamins, weight management Alli) syndrome steatorrhea, oily spotting, Cholestasis flatulence Phentermine (P)/ P: 3.75 mg, T: 23 mg qd Norepinephrine-releasing 7.8% TWL at 1 yr (98) Pregnancy Insomnia, dry mouth, Approved in 2012 for chronic Topiramate ER (T) (Qsymia) (starting dose 3 14 d) agent (P) MAOIs (within 14 d) constipation, paresthesia, weight management Alternative: P: 7.5 mg, T: 46 mg qd 1 GABA receptor Hyperthyroidism dizziness Phentermine (gen) 1 (recommended dose) modulation (T) Glaucoma topiramate (gen) P: 15 mg, T: 92 mg qd (high dose) P: 15 mg qd 1 T: 25 mg bid Naltrexone SR (N)/ N: 8 mg, B: 90 mg Opioid antagonist (N) 1 6.1% TWL at 1 yr (99) Pregnancy Headache, nausea, Approved in 2014 for chronic Bupropion SR (B) 2 tabs bid reuptake inhibitor of Uncontrolled HTN constipation, dizziness weight management (Contrave) Week 1: 1 tab qam dopamine and Seizure disorder Week 2: 1 tab bid norepinephrine (B) Bulimia or anorexia Week 3: 2 tabs qam/1 tab Chronic opioid or opioid qpm agonist use Week 4: 2 tabs bid Alcohol withdrawal MAOIs (within 14 d) h mrcnJunlof Journal American The Liraglutide (Saxenda) 3 mg injectable qd GLP-1 agonist 8.0% TWL at 1 yr (100) Pregnancy Nausea, vomiting, Approved in 2014 for chronic Week 1: 0.6 mg daily; then Personal or family history of pancreatitis weight management increased by 0.6 mg weekly medullary thyroid until 3 mg daily is reached Carcinoma or multiple Endocrine neoplasia Syndrome type 2

GASTROENTEROLOGY Metformin (Glucophage) 500 mg qd (starting dose) Decreases hepatic glucose 2.3 kg additional weight loss Chronic heart failure Nausea, vomiting, diarrhea, Off-label for obesity 1,000 mg bid (max dose) production compared to placebo (101) Metabolic acidosis flatulence Approved for T2DM Decreases intestinal glucose Diabetic ketoacidosis absorption Severe renal disease Primer Obesity Increases peripheral glucose uptake 925 REVIEW ARTICLE 926 Jirapinyo and Thompson

patient preferences but is only one of many factors influencing adherence. Given the relatively equivalent efficacy of different dietary approaches, a diet plan may be chosen based on metabolic risk factors and patient preferences. Specifically, low fat diets induce greater reduction in low-density lipoprotein, whereas low carbohydrate diets are associated with greater improvement in triglycerides, high-density lipoprotein, and HbA1c (41,43–46). Table 4 summarizes the more commonly prescribed diet plans. Off-label for obesity Approved for migraine, seizures Off-label for obesity Approved for depression, smoking cessation Off-label for obesity Approved for T2DM Physical activity is an essential component of a weight loss program. Specifically, at least 150 minutes of aerobic activity per week is recommended (at least 30 minutes per day, most days of the week) (8,47), with at least 2 resistance training days per week (minimum of 1setof8–12 repetitions for a total of 8–10 exercises per week) (48). Resistance training is important because it helps improve muscle REVIEW ARTICLE strength and endurance, modify coronary risk factors, and preserve fat-free mass during weight loss to enhance metabolic rate (49,50). During the weight maintenance phase, higher levels of physical ac- Drowsiness, paresthesia, dizziness Headache, nausea, constipation, dizziness Nausea, vomiting, abdominal pain, increased lipase and amylase tivity of 200–300 minutes per week are recommended (51). Behavioral therapy targets maladaptive eating behaviors, activity, and thinking habits that contribute to obesity. It includes several components. Self-monitoring is perhaps the most im-

ion; ITT, intention-to-treat; MAOI, monoamine oxidase inhibitors; OTC, over-the- portant component of behavioral therapy. Patients are advised to

itor; T2DM, type 2 diabetes mellitus; TWL, total weight loss. record the type, amount, and total calories of their food con- sumption, and physical activity and body weight. Studies show that individuals that routinely record their food intake lose more Pregnancy Recent alcohol use Metabolic acidosis Pregnancy Seizure disorder Bulimia or anorexia Alcohol withdrawal MAOIs (within 14 d) Personal or family history of medullary thyroid Carcinoma or multiple Endocrine neoplasia Syndrome type 2 weight than those who do not (52). Other components of behavioral therapy include (i) stimulus control (such as storing food out of sight, limiting eating places to the kitchen and dining table, and refraining from eating while engaging in other activities), (ii) problem solving (such as planning meals ahead of time while traveling), (iii) cognitive restructuring (such as recognizing a setback as a temporary lapse and continuing to move forward

8.6% TWL at 1 yr instead of giving up), and (iv) relapse prevention focusing on – 14.9% TWL at 1 yr (104) Pregnancy

– high-risk situations (such as vacations, illness, or periods of high compared to placebo (102) 7.5% (103) stress). Traditionally, behavioral therapy is offered in group sessions of 10–20 individuals by registered dietitians, psychologists, exercise specialists, or other health professionals, with each ses- sion lasting 60–90 minutes. It is often held weekly during the active weight-loss phase (6 months) and may taper to biweekly during the weight-maintenance phase (53). In clinical practice, LM is usually prescribed comprehensively to modify both eating and activity habits. To date, there are 2 landmark studies evaluating the efficacy of LM: the Diabetes GABA receptor modulation 5.3 kg additional weight loss Reuptake inhibitor of dopamine and norepinephrine GLP-1 agonist 6% Prevention Program and Look AHEAD studies (54). The Di- abetes Prevention Program study compared LM (16 sessions during the first 6 months, followed by monthly contacts) with metformin with placebo at delaying or preventing development of type 2 diabetes (T2DM) in 3,200 patients with impaired glucose tolerance. At 1 year, LM patients lost 7 kg compared with 0.1 kg for placebo. The risk of developing T2DM was reduced by 58% in the LM group compared with placebo and 31% compared with metformin. At 10 years, participants regained almost all of their Increase by 25 mg/wk 200 mg bid (max dose) 400 mg qd mg qd for 30 d; thenqd 14 (if mg needed) SC: 0.25 mg qw for 4then weeks; 0.5 mg qw for 4 wk; then 1 mg qw for 4 wk; then 1.7 mg qw for 4 wk; then 2.4 mg qw lost weight (with no differences in weight loss among groups).

) Nevertheless, the incidence of T2DM remained the lowest in the LM group (55). In comparison, the Look AHEAD study evaluated the eﬀect of intensive lifestyle intervention (ILI) (24 sessions during the ﬁrst 6 months, followed by 18 sessions in months continued ( 7–12) vs usual care (diabetes support and education) in 5,100 overweight participants with T2DM. At 1 and 4 years, patients in the ILI and diabetes support and education experienced 8.6% vs counter; SC: subcutaneous; SNRI, serotonin-norepinephrine reuptake inhibitor; SR, sustained release; SSRI, selective serotonin reuptake inhib Table 5. MedicationsTopiramate (Topamax) 25 mg qpm (starting dose) Dosage/titration Mechanisms of action EfficacyCVD, cardiovascular disease; ER, extended release; GABA, Contraindications gamma-aminobutyric acid; gen, generic; GLP-1, glucagon-like peptide-1; HTN, hypertens Common side effects FDA status Bupropion SR (Wellbutrin) 300 mg qd Semaglutide (Ozempic) Oral: 3 mg qd for 30 d; then 7 0.7% TWL and 4.7% vs 1.1% TWL, respectively. The ILI group

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Figure 1. Primary bariatric endoscopic interventions. BMI, body mass index; GI, gastrointestinal; ITT, Intention-to-treat; TWL, total weight loss.

Figure 2. Bariatric surgeries. Outcome data from meta-analyses or largest available series. DI, duodeno-ileal; EWL, excess weight loss; GEJ, gastroesophageal junction; GJA, gastrojejunal; ICV, ileocecal valve; II, ileoileal; JJA, jejunojejunal; PE, pulmonary embolism; SBO, small bowel obstruction; TWL, total weight loss.

also experienced signiﬁcantly greater improvement in HbA1c Pharmacotherapy and several measures of cardiovascular diseases (56,57). Weight-loss medications may be considered when patients fail Overall, a comprehensive LM program should be in- to respond to lifestyle modiﬁcation and have a BMI of $30 or corporated as part of every weight loss intervention. LM alone $27 kg/m2 with obesity-related comorbidities (8,60). Before may result in weight loss ranging from 1.4% to 8.6% TWL initiation of a weight-loss medication, current medications depending on the intensity (56,58,59). Key components to success should be reviewed to identify any that are associated with include a diet plan that patients can adhere to, incorporation of weight gain and should be substituted with more weight-neutral physical activity, and a behavioral treatment plan to reinforce the medications (Table 2). To date, there are 5 antiobesity medi- necessary strategies to maintain the lost weight. cations approved by the Food and Drug Administration

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Table 6. Complications of common bariatric surgeries

Time of onset since Complications surgery Diagnostic modalities Management strategies Sleeve gastrectomy Sleeve leaks Post-operative or early Cross-sectional imaging Depends on time from surgery Esophageal stent for acute leaks Pigtail stents for chronic leaks Sleeve stenosis Anytime Distinguish between stenosis and twisting; Hydrostatic or pneumatic balloon dilation of sleeve consider imaging depending on time from surgery and degree of stenosis Twisted sleeve less likely to respond Reflux and its Late Upper endoscopy High dose PPI 1/2 sucralfate for acid reflux

complications Cholestyramine for bile reflux REVIEW ARTICLE Surgical conversion to RYGB Roux-en-Y gastric bypass Surgical leaks Post-operative or early Cross-sectional imaging Depends on location of leak and time from surgery High false negative rates for all studies Esophageal stents for acute pouch and GJ leaks Clips for JJ leaks Pigtail drainage for chronic walled-off leaks GJA ulceration Early or late Do not advance endoscope deeply beyond High dose PPI (soluble form) 1/2 sucralfate area of ulceration Treat H. pylori if positive Helicobacter pylori stool antigen or Stop smoking and optimize glycemic control serology Stop NSAIDs Consider suture removal GJA stenosis Late Upper endoscopy Stepwise endoscopic balloon dilation Avoid UGI series given aspiration risk Do not overdilate (#15 mm) Look for concomitant ulceration Carefully direct wire into Roux limb Foreign body removal Consider LAMS for selected cases Gastrogastric fistula Early or late Upper GI series sensitive If asymptomatic, PPI 1 dietary counseling Upper endoscopy important to confirm If symptomatic, closure (endoscopic [,1 cm] vs surgical) and rule out ulceration Intestinal obstruction Early or late Cross-sectional imaging while Surgery symptomatic to look for intussusception Endoscopy is not indicated for extraluminal causes of and internal herniation obstruction Choledocholithiasis Late RUQ ultrasound Device-assisted enteroscopy Cross-sectional imaging Laparoscopic-assisted ERCP MRCP EUS-directed ERCP IR-guided percutaneous drainage Dilated GJA Late Upper endoscopy Endoscopic revision (TORe) Dilation confirmed with GJA .15 mm APC for incompetent yet not markedly dilated GJA Laparoscopic adjustable gastric band Reflux esophagitis Late Upper endoscopy High dose PPI 1/2 sucralfate Band deflation Esophageal dilatation Late Upper endoscopy Band deflation Upper GI series Surgical replacement or conversion Band erosion Late Upper endoscopy Endoscopic removal of band if buckle is visible with surgical removal of port Band slippage Late Upper GI series Surgery

APC, argon plasma coagulation; ERCP,endoscopic retrograde cholangiopancreatography; EUS, endoscopic ultrasound; GJ, gastrojejunal; GJA, gastrojejunal anastomosis; IR, interventional radiology; JJ, jejunojejunal; LAMS, lumen-apposing metal stent; MRCP, magnetic resonance cholangiopancreatography; PPI, proton pump inhibitor; RUQ, right upper quadrant; TORe, transoral outlet reduction.

(FDA)—phentermine, orlistat (Xenical), phentermine/ months. Obalon is a 3-balloon system, filled with nitrogen gas, topiramate (Qsymia), naltrexone/bupropion (Contrave), and swallowed 4 weeks apart, with positioning confirmed via x-ray or liraglutide (Saxenda) (Table 5). With the exception of orlistat, magnetic resonance. All balloons are removed endoscopically at 6 which blocks absorption of 25%–30% of fat calories, these months. An Orbera meta-analysis (17 studies/1,638 patients) medications target appetite mechanisms specificallybyworking demonstrated an 11.3% TWL at 12 months. The most common in the arcuate nucleus to stimulate pro-opiomelanocortin neu- AEs were pain and nausea (33.7%). The severe adverse event rons to promote satiety. It is important to discuss both potential (SAE) rate was 1.6%, including migration (1.4%), perforation benefits and adverse events of each medication before its initi- (0.1%), and death (0.08%) (66). For Obalon, a randomized sham- ation and to document the conversation, especially when the controlled trial revealed a 6.9% TWL at 12 months with an SAE medication is used off-label. Furthermore, pregnancy is con- rate of 0.4% (67). However, the real-world experience (1,343 traindicated for all weight-loss medications, and patients should patients) showed a 10% TWL with an SAE rate of 0.15% including be advised to use dual contraceptive methods. severe abdominal pain and gastric perforation (68). Although there is no generalizable hierarchical algorithm for Gastric remodeling may be performed via endoscopic sutur- medication selection, specific medications are preferred in certain ing or plication and dates back to as early as 2008 (69–71). Cur- REVIEW ARTICLE clinical settings based on efficacy, adverse events, warnings, rently, there are 2 devices that are cleared by the FDA for tissue contraindications, organ clearance, and mechanisms of action approximation and are used for this purpose, however, without (61). For example, phentermine/topiramate should be considered specific weight loss claims—Overstitch (Apollo Endosurgery) in patients with migraine, bupropion/naltrexone for those with and Incisionless Operating Platform (USGI Medical, San Clem- smoking or depression history, and liraglutide for those with ente, CA). Endoscopic sleeve gastroplasty is the most common diabetes/prediabetes. In addition, certain medications should be gastric remodeling procedure that involves placing several su- avoided in patients with specific comorbidities. For example, tures in a running fashion along the greater curvature. A second patients with uncontrolled hypertension or a history of heart layer of sutures may also be placed medially for reinforcement disease should not be prescribed phentermine. Patients with an (72). A meta-analysis (8 studies/1772 patients) revealed its effi- elevated seizure risk should avoid bupropion/naltrexone. cacy to be 16.5% TWL at 12 months and an SAE rate of 2.2% An effective response is defined as $5% TWL at 3 months including pain/nausea, bleeding, perigastric leak, and fluid col- after the initiation of a weight-loss medication. If the response is lection (73). At 5 years, a single center study (56 of 68 patients deemed ineffective (,5% TWL at 3 months) or if safety or in- who were eligible for the 5-year follow-up from the original co- tolerability issue arises, the medication should be discontinued hort of 216 patients) revealed a 15.9% TWL (compared with and switched to an alternative medication or treatment ap- 15.6% at 1 year) (74). In comparison, gastric plication, also known proach (26). as Primary Obesity Surgery Endoluminal (POSE), involves Gelesis100 is a procedureless intervention that was FDA- placement of tissue plications in the stomach. In contrast to en- approved based on pharmacotherapy thresholds and represents a doscopic sleeve gastroplasty which may be endoscopically re- new class of obesity treatments. It is a hydrogel capsule that is versible, POSE focuses on serosal apposition and is not reversible. orally administered with water before a meal. When hydrated, The traditional POSE procedure involves placement of plications Gelesis100 occupies about one-fourth of the gastric volume. The primarily in the fundus (75). A more recent pattern, also known particles maintain their gel form while passing through the small as distal POSE or POSE2, however, involves placement of plica- intestine before breaking down in the colon. A pivotal trial tions solely in the gastric body (76–78). A meta-analysis (5 (GLOW trial) randomized 436 patients to Gelesis100 vs placebo. studies/586 patients) demonstrated that traditional POSE was At 6 months, the Gelesis100 group experienced 6.4% TWL (vs associated with 12.1% and 13.2% TWL at 6 and 12–15 months, 4.4% TWL for placebo), with 59% achieving $5% TWL (62). This respectively, with an SAE rate of 3.2% including chest pain, low- technology is not yet commercially available. grade fever, extragastric bleeding, and hepatic abscess (79). With In addition to the medications listed above, there are several the new plication pattern, the efficacy seemed to be higher with antiobesity agents under development and currently undergoing approximately 15% and 17.5% TWL at 6 and 9 months, re- clinical trial. For a new drug to be approved for weight loss, it must spectively (76–78,80). Preliminary results suggest that patients meet the FDA thresholds, defined as significant placebo-adjusted with class III obesity may experience greater weight loss (19-20% weight loss of $5% TWL at 1 year or $35% of patients achieving TWL at 1 year) following ESG or distal POSE compared to those $5% TWL (which must be at least twice that induced by placebo). with class I and II (80,81). Aspiration therapy removes a portion of food from the Bariatric Endoscopy stomach after ingestion. The system consists of a large fenestrated Bariatric endoscopy may be divided into gastric and small bowel gastrostomy tube (A-tube), an external port at the skin for aspi- interventions (63,64). In general, gastric interventions primarily ration, and a portable device to perform aspiration. The A-tube is induce weight loss with secondary effects on metabolic condi- placed endoscopically via a standard pull technique, and the port tions. By contrast, small bowel interventions have direct effects on is attached at 1–2 weeks. A meta-analysis (5 studies/590 patients) metabolic conditions with or without weight loss. To date, there demonstrated a 17.8% TWL at 1 year with an SAE rate of 4.1% are 3 types of bariatric endoscopic devices that are FDA-approved including buried bumper, peritonitis, abdominal pain, and and available (Figure 1). product malfunction (82). Intragastric balloons occupy space in the stomach and seem to In addition to weight loss efficacy, all of the approved gastric alter gastric motility (65). There currently are 2 IGBs available in devices and/or procedures discussed above have been shown to the United States—Orbera (Apollo Endosurgery, Austin, TX) and improve obesity-related comorbidities, such as diabetes and fatty Obalon (Obalon Therapeutics, Carlsbad, CA). Orbera is a single liver (82–86). The effect of endoscopic bariatric procedures on fluid-filled balloon that is placed and removed endoscopically at 6 conception, however, remains unknown.

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Other gastric devices including the Spatz and Elipse balloon Gastroenterologists should routinely ask for prebariatric surgical, systems are currently undergoing FDA review, whereas some nadir, and current weights. If weight regain is encountered, re- small bowel interventions such as duodenal-jejunal bypass liner ferral to a multidisciplinary team, including dietitian, obesity and duodenal mucosal resurfacing are undergoing US clinical medicine expert, bariatric endoscopist, and bariatric surgeon, for trials. According to the ASGE/ASMBS, a new endoscopic pro- consideration of pharmacotherapy and/or endoscopic revision of cedure intended as a primary obesity intervention should achieve bariatric surgery is recommended. There are several eﬀective $25% excess weight loss (EWL) at 1 year with a minimum of 15% endoscopic treatment options for weight regain; however, this is EWL over control with an SAE rate ,5% (87). beyond the scope of this article.

DEVELOPING EXPERTISE IN OBESITY MEDICINE AND Bariatric surgery BARIATRIC ENDOSCOPY Bariatric surgery should be considered for patients with a BMI of There are several resources available for gastroenterologists who $ $ 2 40 or 35 kg/m with at least 1 comorbidity (88). Although plan on specializing in Obesity Medicine and Bariatric Endoscopy several bariatric surgical procedures are available (Figure 2), SG (95). These programs focus on cognitive elements, skill set de- and RYGB remain the most commonly performed. velopment, and center requirements. American Board of Obesity REVIEW ARTICLE SG involves removal of the fundus and greater curvature to Medicine credentialing is also available for board-certified gas- create a tubular structure along the lesser curvature. The small troenterologists without the need for additional training. bowel remains unaltered. A meta-analysis (11 studies/over 3,000 From a center standpoint, there are also several infrastructure patients) revealed that patients experienced 51.5% EWL at 1 year. and personnel considerations. These include having a patient- The pooled mortality rate was 0.6% with an AE rate of 8.9% and friendly waiting area (such as wide chairs and reinforced toilets) reoperation rate of 3% (89). In a single center study, 51 of the and medical equipment (such as extra-large blood pressure cuffs original cohort of 165 patients experienced 60.5% EWL at 5 years and bariatric scales). Staff training to reduce bias and stigma and (compared with 82% EWL at 1 year) (90). to encourage the use of people-first language and terms such as RYGB is the preferred surgery for patients with obesity and unhealthy weight rather obese is also encouraged. Furthermore, a fl concomitant metabolic diseases or gastroesophageal re ux dis- multidisciplinary team, which includes bariatric surgeons, bari- ease. During RYGB, the stomach is divided into a small pouch and atric endoscopists, obesity medicine experts, dietitians, psychol- a larger remnant stomach. The jejunum is transected, followed by ogists, health coaches, and/or social workers, is essential and can connecting one end to the pouch at the gastrojejunal anastomosis be assembled with the help of modern virtual platforms. In ad- and the other end to the proximal jejunum at the jejunojejunal dition, these platforms may be used as part of the aftercare pro- anastomosis. A meta-analysis (17 studies/over 8,000 patients) gram. Moreover, fitness applications and calorie tracking devices revealed that patients experienced 63.3% EWL at 1 year after may be useful to encourage adherence to LM. RYGB. The pooled mortality rate was 1.1% with an AE rate of 12% and reoperation rate of 5.3% (89). At 12 years, the average weight CONCLUSION 5 loss is 27% TWL (n 387) (91). Gastroenterologists will continue to see an increasing number of In addition to SG and RYGB, other procedures that are still patients with obesity. These patients are at greater risk of GI being performed at a smaller proportion include gastric banding comorbidities and require special consideration. Similarly, bari- and biliopancreatic diversion with duodenal switch. Further- atric surgery carries various complications that necessitate unique more, there are several emerging procedures, such as minigastric management strategies. Finally, gastroenterologists are well po- bypass and single anastomosis duodenoileal bypass with sleeve sitioned to manage obesity medically and endoscopically and gastrectomy, which gastroenterologists should become familiar should adopt a greater role in addressing this pandemic. with (Figure 2). CONFLICTS OF INTEREST ENDOSCOPIC MANAGEMENT OF BARIATRIC Guarantor of the article: Christopher C. Thompson, MD, MSc. SURGICAL COMPLICATIONS Specific author contributions: P.J.: wrote the manuscript. C.C.T.: As the number of bariatric surgeries continues to rise, gastroen- critically reviewed the article for important intellectual content. All terologists will see more patients with surgically altered anatomy. authors approved the final draft of the article. In addition to understanding normal and abnormal endoscopic Financial support: NIH T32 DK007533 and P30 DK034854. findings in this patient population (see above), gastroenterolo- Potential competing interests: P.J. has received research support gists should be familiar with potential complications and their from Apollo Endosurgery - Research Support, Boston Scientific- management. Table 6 summarizes complications after each of the Research Support, Endogastric Solutions - Consultant, Fractyl - common bariatric surgeries, presenting symptoms, and man- Research Support, GI Dynamics - Consultant (Consulting fees), agement strategies (92). Furthermore, nutrient deficiencies may Research Support, Lumendi - Consultant. C.C. Thompson: Apollo be seen after all bariatric surgeries, such as vitamins B1/B12, D, A, Endosurgery - Consultant/Research Support (Consulting fees/ folate, iron, and calcium, with the addition of zinc and copper for Institutional Research Grants), Aspire Bariatrics - Research Support biliopancreatic diversion with duodenal switch and RYGB (Institutional Research Grant), BlueFlame Healthcare Venture Fund (93,94). Therefore, adherence to vitamin supplements should be - General Partner, Boston Scientific - Consultant (Consulting fees)/ assessed with a low threshold to check these levels, especially for Research Support (Institutional Research Grant), Covidien/ those who are not routinely followed by bariatric surgery. In Medtronic - Consultant (Consulting fees), EnVision Endoscopy - addition, weight regain after bariatric surgery is not uncommon Board Member, ERBE - Institutional Research Grant, Fractyl - and is likely caused by several etiologies including medical, be- Consultant/Advisory Board Members (Consulting fees), FujiFilm - havioral, hormonal, pharmacologic, and anatomical factors. Institutional Research Grant, GI Dynamics - Consultant (Consulting

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