Mesenteric fat cryolipolysis attenuates insulin resistance in the Ossabaw swine model of the metabolic syndrome.

BACKGROUND: The rising prevalence of insulin resistance (IR), metabolic syndrome, and type 2 diabetes are associated with increases in abdominal mesenteric fat. Adipocytes are sensitive to low temperatures, making cryolipolysis of mesenteric fat an attractive treatment modality to potentially reduce IR. OBJECTIVES: We aimed to determine whether (1) cryolipolysis is safe in reducing the volume of the mesenteric fat and (2) reduction in mesenteric fat volume reduces indices of IR and glycemic dysfunction. SETTING: Indiana University School of Medicine. METHODS: A novel cooling device and method delivered cryolipolysis in a controlled manner to avoid tissue ablative temperatures. Ossabaw pigs (n = 8) were fed a high-fat diet for 9 months to develop visceral obesity, IR, and metabolic syndrome. Following laparotomy, mesenteric fat cryolipolysis (MFC) was performed in 5 pigs, while 3 served as sham surgery controls. The volume of the mesenteric fat was measured by computed tomography and compared with indices of glucose intolerance before and at 3 and 6 months postprocedure. RESULTS: MFC safely reduced mesenteric fat volume by ∼30% at 3 months, which was maintained at 6 months. Body weight did not change in either the MFC or sham surgery control groups. Measure of glycemic control, insulin sensitivity, and blood pressure significantly improved after MFC compared with sham controls. CONCLUSION: MFC reduces the volume of mesenteric fat and improves glycemic control in obese, IR Ossabaw pigs, without adverse effects.

Implementation of entrustable professional activities into fellowship council accredited programs: a pilot project.

OBJECTIVE: The Fellowship Council (FC) is transitioning to a competency-based medical education (CBME) model, including the introduction of Entrustable Professional Activities (EPAs) for training and assessment of Fellows. This study describes the implementation process employed by the FC during a ten-month pilot project and presents data regarding feasibility and perceived value. METHODS: The FC coordinated the development of EPAs in collaboration with the sponsoring societies for Advanced GI/MIS, Bariatrics, Foregut, Endoscopy and Hepatopancreaticobiliary (HPB) fellowships encompassing the preoperative, intraoperative, and postoperative phases of care for key competencies. Fifteen accredited fellowship programs participated in this project. The assessments were collected through a unique platform on the FC website. Programs were asked to convene a Clinical Competency Committee (CCC) on a quarterly basis. The pilot group met monthly to support and improve the process. An exit survey evaluated the perceived value of EPAs. RESULTS: The 15 participating programs included 18 fellows and 106 faculty. A total of 655 assessments were initiated with 429 (65%) completed. The average (SD) number of EPAs completed for each fellow was 24(18); range 0-72. Intraoperative EPAs were preferentially completed (71%). The average(SD) time for both the fellow and faculty to complete an EPA was 27(78) hours. Engagement increased from 39% of fellows completing at least one EPA in September to 72% in December and declining to 50% in May. Entrustment level increased from 6% of EPAs evaluated as "Practice Ready" in September to 75% in June. The exit survey was returned by 63% of faculty and 72% of fellows. Overall, 46% of fellows and 74% of program directors recommended full-scale implementation of the EPA framework. CONCLUSION: A competency-based assessment framework was developed by the FC and piloted in several programs. Participation was variable and required ongoing strategies to address barriers. The pilot project has prepared the FC to introduce CBME across all FC training programs.

Defining benchmarks for fellowship training in foregut surgery: a 10-year review of fellowship council index cases.

INTRODUCTION: Surgical treatment of foregut disease is a complex field that demands advanced expertise to ensure favorable outcomes for patients. To address the growing need for foregut surgeons, leaders within several national societies have become interested in developing a foregut fellowship. The aim of this study was to develop data-driven benchmarks that will aid in defining appropriate accreditation criteria for these fellowships. METHODS: We obtained case log data for Fellowship Council fellows trained from 2009-2019. We identified 78 complex foregut (non-bariatric) case codes and divided them into 5 index case categories including (1) hiatal/paraoesophageal hernia repair, (2) fundoplication, (3) esophageal myotomy, (4) major organ resection, and (5) minor organ resection. Median volumes in each index category were compared over time using Kruskall-Wallis tests. The share of cases done using open, laparoscopic, or robotic approaches were analyzed using linear regression analysis. RESULTS: For the 10 years analyzed, 1362 fellows logged 82,889 operations and 111,799 endoscopies. Median foregut cases per fellow grew significantly from 42 (IQR = 24-74) cases in 2010 to 69 (IQR = 33-106) cases in 2019. Median endoscopy volumes also grew significantly from 42 (IQR = 7-88) in 2010 to 69 (IQR 32-123) in 2019.The volume of hiatal/paraoesophageal hernia repairs increased significantly over time while volumes in the remaining 4 index categories remained stable. The share of robotic cases exhibited near perfect linear growth from 2.2% of all foregut cases in 2010 to 14.4% in 2019 (R = 0.99, p < 0.0001). Open cases exhibited linear decay from 7.2% of cases in 2010 to 4.7% of cases in 2019 (R = 0.92, p = 0.0001). Laparoscopic/thoracoscopic cases also exhibited linear decay from 90.6% of cases in 2010 to 80.9% of cases in 2019 (R = 0.98, p < 0.00001). CONCLUSIONS: FC fellows are exposed to robust volumes of foregut cases. This rich data set provides an evidence-based guide for establishing criteria for potential foregut fellowships.

First report from the American Society of Metabolic and Bariatric Surgery closed-claims registry: prevalence, causes, and lessons learned from bariatric surgery medical malpractice claims.

BACKGROUND: Bariatric surgery has demonstrated sustained improvements in quality. Malpractice closed claims have been offered as a means of assessing quality. Few studies have investigated malpractice closed claims and opportunities for improvement in bariatric surgery. OBJECTIVES: To examine the prevalence and causes of malpractice claims with examination of prospects for quality improvement. SETTING: University hospital, United States; private practice. METHODS: Four national malpractice insurers participated in the closed-claims registry. Data regarding patients, staff, procedures, and hospital status were gathered from closed-claims files. Following data collection, a clinical summary of each closed claim was collected and later assessed by an expert panel on the basis of the following: contributing diagnosis and treatment events; whether complications were potentially preventable by the surgeon; the role of language, fatigue, distraction, workload, or teaching hospital/trainee supervision; communication concerns; and final care determination. RESULTS: A total of 175 closed claims were collected from index bariatric surgeries within the period from 2006-2014. Of these, 75.9% of surgeons were board certified and 43.3% of the hospitals were accredited for bariatric surgery. Most clinical complications after bariatric surgery that led to malpractice lawsuits were mortality (35.1%) and leaks (17.5%). While they were not the common cause for malpractice suits, bleeding (5.3%), retained foreign body (5.3%), and vascular injury (4.4%) occurred at higher rates than national averages. CONCLUSION: Prevalence of malpractice claims regarding bariatric surgery is low. Failure to diagnose, delay in treatment, postoperative care, and communication domain responses indicate future opportunities for improvement.

Gender disparities in gastrointestinal surgery fellowship programs.

BACKGROUND: Gender disparities in surgical leadership have come under increased scrutiny, and in order to better understand why these disparities exist, it is important to study the disparities across surgical fellowship programs. METHODS: Data derived from the Fellowship Council (FC) database for fellows completing training from academic years 2015-2019 were analyzed. Available information included institution, fellowship type, program director (PD), associate program director (APD), faculty, and fellow names for all FC Fellowships. Faculty and fellow gender were determined from personal knowledge or publicly available online biographical information. RESULTS: A total of 1023 fellows and 221 programs were analyzed. The advanced gastrointestinal (GI)/minimally invasive surgery (MIS) fellowship programs included 321 fellows, with a small increase in the percentage of female fellows from 28 to 31% over 5 years. Advanced GI/MIS/bariatric fellowship programs had a total of 262 fellows, also with a small increase in the percent of female fellows, from 29 to 38% in the study period. The gender of program directors, assistant program directors, and faculty for the fellowship programs studied were analyzed as well. Of the 221 programs in the Fellowship Council data, 13.6% of program directors, 18.3% of associate program directors, and 19.9% of faculty were female. Advanced GI/MIS fellowship programs had the lowest percentage of female PDs, with only 9.3% of the program directors being female. Colorectal surgery fellowships had the highest percentage of female PDs, with 33% being female. CONCLUSIONS: In conclusion, women are underrepresented in gastrointestinal surgery fellowships among both trainees and educators. It is likely that a significant contributing factor to this underrepresentation of female fellows is the underrepresentation of female program directors and faculty; although neither our study nor any previously published study has proven that statistically.

Measuring ketone bodies for the monitoring of pathologic and therapeutic ketosis.

BACKGROUND: The ketone bodies ß-hydroxybutyrate (BOHB) and acetone are generated as a byproduct of the fat metabolism process. In healthy individuals, ketone body levels are ∼0.1 mM for BOHB and ∼1 part per million for breath acetone (BrAce). These levels can increase dramatically as a consequence of a disease process or when used therapeutically for disease treatment. For example, increased ketone body concentration during weight loss is an indication of elevated fat metabolism. Ketone body measurement is relatively inexpensive and can provide metabolic insights to help guide disease management and optimize weight loss. METHODS: This review of the literature provides metabolic mechanisms and typical concentration ranges of ketone bodies, which can give new insights into these conditions and rationale for measuring ketone bodies. RESULTS: Diseases such as heart failure and ketoacidosis can affect caloric intake and macronutrient management, which can elevate BOHB 30-fold and BrAce 1000-fold. Other diseases associated with obesity, such as brain dysfunction, cancer, and diabetes, may cause dysfunction because of an inability to use glucose, excessive reliance on glucose, or poor insulin signaling. Elevating ketone body concentrations (e.g., nutritional ketosis) may improve these conditions by forcing utilization of ketone bodies, in place of glucose, for fuel. During weight loss, monitoring ketone body concentration can demonstrate program compliance and can be used to optimize the weight-loss plan. CONCLUSIONS: The role of ketone bodies in states of pathologic and therapeutic ketosis indicates that accurate measurement and monitoring of BOHB or BrAce will likely improve disease management. Bariatric surgery is examined as a case study for monitoring both types of ketosis.

American Society for Metabolic and Bariatric Surgery 2018 estimate of metabolic and bariatric procedures performed in the United States.

BACKGROUND: Metabolic and bariatric surgery, despite being the only effective durable treatment for obesity, remains underused as approximately 1% of all patients who qualify undergo surgery. The American Society for Metabolic and Bariatric Surgery created a Numbers Taskforce to specify annual rate of utilization for obesity treatment interventions and to determine if patients in need are receiving appropriate therapy. OBJECTIVES: The objective of this study was to provide the best estimated number of metabolic and bariatric procedure performed in the United States in 2018. SETTING: United States. METHODS: We reviewed data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program, National Surgical Quality Improvement Program, Bariatric Outcomes Longitudinal Database, and Nationwide Inpatient Sample. In addition, data from industry and outpatient centers were used to estimate outpatient center activity. Data from 2018 were compared mainly with data from the previous 2 years. RESULTS: Compared with 2017, the total number of metabolic and bariatric procedures performed in 2018 increased from approximately 228,000 to 252,000. The sleeve gastrectomy continues to be the most common procedure. The gastric bypass procedure trend remained relatively stable and the gastric band procedure trend continued to decline. The percentage of revision procedures and biliopancreatic diversion with duodenal switch procedures increased slightly. Finally, intragastric balloons placement continues as a significant contributor to the cumulative total number of procedures performed but declined from the previous year. CONCLUSIONS: There was a 10.8% increase in the number of metabolic and bariatric procedures performed in 2018, compared with 2017, with an overall increase of approximately 60% since 2011. When taking into account primary procedures only, approximately 1.1% of patients who qualified for metabolic and bariatric surgery were treated with surgery in 2018.

Mechanisms of Weight Loss After Sleeve Gastrectomy and Adjustable Gastric Banding: Far More Than Just Restriction.

Obesity has reached global epidemic proportions in recent decades. Bariatric surgery is currently accepted as most effective in alleviating morbid obesity and related disorders. Sleeve gastrectomy (SG) and adjustable gastric banding (AGB) have gained popularity since the beginning of this century because of their efficacy, safety, and simplicity. SG, in particular, has emerged as the most popular bariatric procedure because of its simpler concept and shorter operative time compared with gastric bypass. Caloric restriction, however, cannot account for the sustained weight loss and improved glucose metabolism seen following SG and AGB. Other mechanisms, including changes in gastrointestinal hormone secretion, rearrangement of hypothalamic and vagal control, alteration in energy expenditure, and re-regulation of bile acid metabolism and the intestinal flora environment, are thought to contribute to the postoperative benefits. This review focuses on clinical and experimental literature addressing the potential mechanisms for SG and AGB procedures in human and animal models. Understanding such mechanisms can provide important insight into how current gastric restrictive procedures work and how future treatments of obesity, both surgical and nonsurgical, can be developed.

Laparoscopic vagal nerve blocking device explantation: case series and report of operative technique.

BACKGROUND: Vagal nerve blockade with the vBloc device (ReShape Lifesciences, St. Paul, MN) has been shown to provide durable 2-year weight loss in patients with moderate obesity. These devices may require removal. We present a series of patients and report our technique for laparoscopic removal of this device. METHODS: From December 2009 to December 2016, the medical records of patients who underwent laparoscopic explantation of a vagal blocking device at our institution were retrospectively reviewed. All patients initially underwent device placement as part of a multi-center, randomized, controlled trial. The device leads were removed with the application of firm traction in order to safely dissect them away from the stomach and esophagus as the body tended to form a fibrotic capsule surrounding the leads. Operative details, length of stay, 30-day post-operative complications, demographics and reasons for device removal were reported. RESULTS: Thirty patients were identified. Median age was 54 (37-65) years. Average operative time was 227.63 (± 100.21) min. Median time from implantation to removal was 41 (11-96) months. Removal reasons included device malfunction (7 patients, 23.3%), pain at the neuroregulator site (5 patients, 16.7%), retrosternal or epigastric pain (11 patients, 36.7%), weight regain or dissatisfaction with weight loss (15 patients, 50%), and severe nausea (2 patients, 6.7%). Two patients (6.7%) had Clavien-Dindo grade II complications following explantation. Thirteen patients (43.3%) had dense adhesions noted at the time of operation. Seroma formation at the neuroregulator site was the most common complication (7 patients, 23.3%). CONCLUSION: The vagal nerve blocking device can be safely removed laparoscopically with a low 30-day complication rate. Surgeons should be familiar with the details of the device appearance, the typical lead location, and should anticipate dense adhesions surrounding the leads. In addition, experience operating in the region of the gastroesophageal junction is imperative.

ASMBS pediatric metabolic and bariatric surgery guidelines, 2018.

The American Society for Metabolic and Bariatric Surgery Pediatric Committee updated their evidence-based guidelines published in 2012, performing a comprehensive literature search (2009-2017) with 1387 articles and other supporting evidence through February 2018. The significant increase in data supporting the use of metabolic and bariatric surgery (MBS) in adolescents since 2012 strengthens these guidelines from prior reports. Obesity is recognized as a disease; treatment of severe obesity requires a life-long multidisciplinary approach with combinations of lifestyle changes, nutrition, medications, and MBS. We recommend using modern definitions of severe obesity in children with the Centers for Disease Control and Prevention age- and sex-matched growth charts defining class II obesity as 120% of the 95th percentile and class III obesity as 140% of the 95th percentile. Adolescents with class II obesity and a co-morbidity (listed in the guidelines), or with class III obesity should be considered for MBS. Adolescents with cognitive disabilities, a history of mental illness or eating disorders that are treated, immature bone growth, or low Tanner stage should not be denied treatment. MBS is safe and effective in adolescents; given the higher risk of adult obesity that develops in childhood, MBS should not be withheld from adolescents when severe co-morbidities, such as depressed health-related quality of life score, type 2 diabetes, obstructive sleep apnea, and nonalcoholic steatohepatitis exist. Early intervention can reduce the risk of persistent obesity as well as end organ damage from long standing co-morbidities.

Risk factors for early postoperative complications after bariatric surgery.

PURPOSE: Vertical sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are currently the most common bariatric procedures. Although the safety of these operations has markedly improved, there continues to be a certain rate of complications. Such adverse events can have a significant deleterious effect on the outcome of these procedures and represent a costly burden on patients and society at large. A better understanding of these complications and their predictive factors may help ameliorate and optimize outcomes. METHODS: Seven hundred seventy-two consecutive patients who underwent SG or RYGB for morbid obesity between January 2011 and October 2015, in the Division of Bariatric Surgery at a tertiary institution, were included through retrospective review of the medical database. The complications were categorized and evaluated according to severity using the Clavien-Dindo classification system. Significant risk factors were evaluated by binary logistic regression to identify independent predictors and analyzed to identify their relationship with the type of complication. RESULTS: Independent predictors of severe complication after these procedures included male gender, open and revisional surgery, hypertension, and hypoalbuminemia. Hypoalbuminemia had significant associations with occurrence of deep surgical site infection and leak. Open surgery had significant associations with occurrence of superficial and deep surgical site infection and respiratory complications. Independent predictors of severe complication after laparoscopic primary RYGB included previous abdominal surgery. Previous abdominal surgery had significant associations with deep surgical site infection and leak. CONCLUSION: Recognition and optimization of these risk factors would be valuable in operative risk prediction before bariatric surgery.

American Society for Metabolic and Bariatric Surgery estimation of metabolic and bariatric procedures performed in the United States in 2016.

BACKGROUND: Bariatric surgery, despite being the most successful long-lasting treatment for morbid obesity, remains underused as only approximately 1% of all patients who qualify for surgery actually undergo surgery. To determine if patients in need are receiving appropriate therapy, the American Society for Metabolic and Bariatric Surgery created a Numbers Taskforce to specify annual rate of use for obesity treatment interventions. OBJECTIVES: The objective of this study was to determine metabolic and bariatric procedure trends since 2011 and to provide the best estimate of the number of procedures performed in the United States in 2016. SETTING: United States. METHODS: We reviewed data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program, National Surgical Quality Improvement Program, Bariatric Outcomes Longitudinal Database, and Nationwide Inpatient Sample. In addition, data from industry and outpatient centers were used to estimate outpatient center activity. Data from 2016 were compared with the previous 5 years of data. RESULTS: Compared with 2015, the total number of metabolic and bariatric procedures performed in 2016 increased from approximately 196,000 to 216,000. The sleeve gastrectomy trend is increasing, and it continues to be the most common procedure. The gastric bypass and gastric band trends continued to decrease as seen in previous years. The percentage of revision procedures and biliopancreatic diversion with duodenal switch procedures increased slightly. Finally, intragastric balloons placement emerged as a significant contributor to the cumulative total number of procedures performed. CONCLUSIONS: There is increasing use of metabolic and bariatric procedures performed in the United States from 2011 to 2016, with a nearly 10% increase noted from 2015 to 2016.

Obesity in America.

BACKGROUND: The prevalence of obesity in America continues to grow significantly. Awareness and understanding of the disease of obesity and treatment options for it appear to be lacking among the general US population. OBJECTIVE: This study aimed to identify misperceptions in diagnosis and treatment of obesity, struggles Americans face in obtaining treatment, consequences of obesity, and perceived barriers to weight loss. SETTING: University hospital, United States. METHODS: A survey of 1509 adults was completed in September 2016 using AmeriSpeak, a probability-based panel designed to be representative of the US household population. The survey included oversamples of blacks and Hispanics. The study analyzed quantitative data from structured interviews and presents descriptive statistics related to public attitudes toward obesity. RESULTS: Of Americans, 81% consider obesity to be the most serious health problem facing the nation, tying cancer as the top issue and landing ahead of diabetes (72%), heart disease (72%), mental illness (65%), and HIV infection and AIDS (46%). Nearly all Americans (94%) agree that obesity itself, even when no other diseases are present, increases the risk for early death. Most Americans overestimate the effectiveness of some obesity treatments, such as diet and exercise alone. Many overweight and obese Americans do not consult a doctor at all about their issues of excess weight. CONCLUSIONS: There is increased awareness about the serious consequences of obesity, but there is still a lack of understanding about the reasons and best treatment modalities for the disease.

Perioperative management of obstructive sleep apnea in bariatric surgery: a consensus guideline.

BACKGROUND: The frequency of metabolic and bariatric surgery (MBS) is increasing worldwide, with over 500,000 cases performed every year. Obstructive sleep apnea (OSA) is present in 35%-94% of MBS patients. Nevertheless, consensus regarding the perioperative management of OSA in MBS patients is not established. OBJECTIVES: To provide consensus based guidelines utilizing current literature and, when in the absence of supporting clinical data, expert opinion by organizing a consensus meeting of experts from relevant specialties. SETTING: The meeting was held in Amsterdam, the Netherlands. METHODS: A panel of 15 international experts identified 75 questions covering preoperative screening, treatment, postoperative monitoring, anesthetic care and follow-up. Six researchers reviewed the literature systematically. During this meeting, the "Amsterdam Delphi Method" was utilized including controlled acquisition of feedback, aggregation of responses and iteration. RESULTS: Recommendations or statements were provided for 58 questions. In the judgment of the experts, 17 questions provided no additional useful information and it was agreed to exclude them. With the exception of 3 recommendations (64%, 66%, and 66% respectively), consensus (>70%) was reached for 55 statements and recommendations. Several highlights: polysomnography is the gold standard for diagnosing OSA; continuous positive airway pressure is recommended for all patients with moderate and severe OSA; OSA patients should be continuously monitored with pulse oximetry in the early postoperative period; perioperative usage of sedatives and opioids should be minimized. CONCLUSION: This first international expert meeting provided 58 statements and recommendations for a clinical consensus guideline regarding the perioperative management of OSA patients undergoing MBS.

Alcohol and other substance use after bariatric surgery: prospective evidence from a U.S. multicenter cohort study.

BACKGROUND: Empirical evidence suggests Roux-en-Y gastric bypass (RYGB) increases risk of developing alcohol use disorder (AUD). However, prospective assessment of substance use disorders (SUD) after bariatric surgery is limited. OBJECTIVE: To report SUD-related outcomes after RYGB and laparoscopic adjustable gastric banding (LAGB). To identify factors associated with incident SUD-related outcomes. SETTING: 10 U.S. hospitals METHODS: The Longitudinal Assessment of Bariatric Surgery-2 is a prospective cohort study. Participants self-reported past-year AUD symptoms (determined by the Alcohol Use Disorders Identification Test), illicit drug use (cocaine, hallucinogens, inhalants, phencyclidine, amphetamines, or marijuana), and SUD treatment (counseling or hospitalization for alcohol or drugs) presurgery and annually postsurgery for up to 7 years through January 2015. RESULTS: Of 2348 participants who underwent RYGB or LAGB, 2003 completed baseline and follow-up assessments (79.2% women, baseline median age: 47 years, median body mass index 45.6). The year-5 cumulative incidence of postsurgery onset AUD symptoms, illicit drug use, and SUD treatment were 20.8% (95% confidence interval (CI): 18.5-23.3), 7.5% (95% CI: 6.1-9.1), and 3.5% (95% CI: 2.6-4.8), respectively, post-RYGB, and 11.3% (95% CI: 8.5-14.9), 4.9% (95% CI: 3.1-7.6), and .9% (95% CI: .4-2.5) post-LAGB. Undergoing RYGB versus LAGB was associated with higher risk of incident AUD symptoms (adjusted hazard ratio or AHR = 2.08 [95% CI: 1.51-2.85]), illicit drug use (AHR = 1.76 [95% CI: 1.07-2.90]) and SUD treatment (AHR = 3.56 [95% CI: 1.26-10.07]). CONCLUSIONS: Undergoing RYGB versus LAGB was associated with twice the risk of incident AUD symptoms. One-fifth of participants reported incident AUD symptoms within 5 years post-RYGB. AUD education, screening, evaluation, and treatment referral should be incorporated in pre- and postoperative care.

Metabolic improvements following Roux-en-Y surgery assessed by solid meal test in subjects with short duration type 2 diabetes.

BACKGROUND: Glucose homeostasis improves within days following Roux-en-Y gastric bypass (RYGB) surgery. The dynamic metabolic response to caloric intake following RYGB has been assessed using liquid mixed meal tolerance tests (MMTT). Few studies have evaluated the glycemic and hormonal response to a solid mixed meal in subjects with diabetes prior to, and within the first month following RYGB. METHODS: Seventeen women with type 2 diabetes of less than 5 years duration participated. Fasting measures of glucose homeostasis, lipids and gut hormones were obtained pre- and post-surgery. MMTT utilizing a solid 4 oz chocolate pudding performed pre-, 2 and 4 weeks post-surgery. Metabolic response to 4 and 2 oz MMTT assessed in five diabetic subjects not undergoing surgery. RESULTS: Significant reductions in fasting glucose and insulin at 3 days, and in fasting betatrophin, triglycerides and total cholesterol at 2 weeks post-surgery. Hepatic insulin clearance was greater at 3 days post-surgery. Subjects exhibited less hunger and greater feelings of fullness and satisfaction during the MMTT while consuming 52.9 ± 6.5% and 51.0 ± 6.5% of the meal at 2 and 4 weeks post-surgery respectively. At 2 weeks post-surgery, glucose and insulin response to MMTT were improved, with greater GLP-1 and PYY secretion. Improved response to solid MMTT not replicated by consumption of smaller pudding volume in diabetic non-surgical subjects. CONCLUSIONS: With a test meal of size and composition representative of the routine diet of post-RYGB subjects, improved glycemic and gut hormone responses occur which cannot be replicated by reducing the size of the MMTT in diabetic subjects not undergoing surgery. TRIAL REGISTRATION: Clinical Trials.gov Identifier: NCT00957957 August 11, 2009.