Food Intake Following Gastric Bypass Surgery: Patients Eat Less but Do Not Eat Differently.

BACKGROUND: Lack of robust research methodology for assessing ingestive behavior has impeded clarification of the mediators of food intake following gastric bypass (GBP) surgery. OBJECTIVES: To evaluate changes in directly measured 24-h energy intake (EI), energy density (ED) (primary outcomes), eating patterns, and food preferences (secondary outcomes) in patients and time-matched weight-stable comparator participants. METHODS: Patients [n = 31, 77% female, BMI (in kg/m2) 45.5 ± 1.3] and comparators (n = 32, 47% female, BMI 27.2 ± 0.8) were assessed for 36 h under fully residential conditions at baseline (1 mo presurgery) and at 3 and 12 mo postsurgery. Participants had ad libitum access to a personalized menu (n = 54 foods) based on a 6-macronutrient mix paradigm. Food preferences were assessed by the Leeds Food Preference Questionnaire. Body composition was measured by whole-body DXA. RESULTS: In the comparator group, there was an increase in relative fat intake at 3 mo postsurgery; otherwise, no changes were observed in food intake or body composition. At 12 mo postsurgery, patients lost 27.7 ± 1.6% of initial body weight (P < 0.001). The decline in EI at 3 mo postsurgery (-44% from baseline, P < 0.001) was followed by a partial rebound at 12 mo (-18% from baseline), but at both times, dietary ED and relative macronutrient intake remained constant. The decline in EI was due to eating the same foods as consumed presurgery and by decreasing the size (g, MJ), but not the number, of eating occasions. In patients, reduction in explicit liking at 3 mo (-11.56 ± 4.67, P = 0.007) and implicit wanting at 3 (-15.75 ± 7.76, P = 0.01) and 12 mo (-15.18 ± 6.52, P = 0.022) for sweet foods were not matched by reduced intake of these foods. Patients with the greatest reduction in ED postsurgery reduced both EI and preference for sweet foods. CONCLUSIONS: After GBP, patients continue to eat the same foods but in smaller amounts. These findings challenge prevailing views about the dynamics of food intake following GBP surgery. This trial was registered as clinicaltrials.gov as NCT03113305.

Evaluation of the impact of gastric bypass surgery on eating behaviour using objective methodologies under residential conditions: Rationale and study protocol.

Gastric bypass surgery leads to significant and sustained weight loss and a reduction in associated health risks in individuals with severe obesity. While reduced energy intake (EI) is the primary driver of weight loss following surgery, the underlying mechanisms accounting for this energy deficit are not well understood. The evidence base has been constrained by a lack of fit-for-purpose methodology in assessing food intake coupled with follow-up studies that are relatively short-term. This paper describes the underlying rationale and protocol for an observational, fully residential study using covert, objective methodology to evaluate changes in 24-hr food intake in patients (n = 31) at 1-month pre-surgery and 3-, 12- and 24-months post-surgery, compared to weight-stable controls (n = 32). The main study endpoints included change in EI, macronutrient intake, food preferences, and eating behaviours (speed, frequency, and duration of eating). Other physiological changes that may influence EI and weight regulation including changes in body composition, circulating appetite hormones, resting metabolic rate, total energy expenditure and gastrointestinal symptoms were also evaluated. Understanding which mechanisms contribute to a reduction in EI and weight loss post-surgery could potentially help to identify those individuals who are most likely to benefit from gastric bypass surgery as well as those that may need more targeted intervention to optimise their weight loss post-surgery. Furthermore, clarification of these mechanisms may also inform targeted approaches for non-surgical treatments of obesity.

The Efficacy of Energy-Restricted Diets in Achieving Preoperative Weight Loss for Bariatric Patients: a Systematic Review.

In bariatric practice, a preoperative weight loss of at least 5% is recommended. However, the hypocaloric diets prescribed vary and no consensus exists. This study examined the efficacy of preoperative diets in achieving 5% weight loss. From a systematic literature search, eight randomised controlled trials (n = 862) were identified. Half of the trials used a "very-low-calorie diet" whilst the rest employed a "low-calorie diet". Only five diets achieved ≥ 5% weight loss over varying durations and energy intakes. By inference, compliance with a 700-1050 kcal (2929-4393 kJ) diet, consisting of moderate carbohydrate, high protein and low/moderate fat, for 3 weeks is likely to achieve 5% weight loss. A low-carbohydrate diet (< 20 g/day) may achieve this target within a shorter duration. Additional research is required to validate these conclusions.

Laparoscopic sleeve gastrectomy for morbidly obese adolescents in Singapore.

INTRODUCTION: Laparoscopic sleeve gastrectomy (LSG) outcomes among adolescents and factors associated with adolescent obesity in Singapore were evaluated. METHODS: Prospectively collected data of patients aged 16-19 years who underwent LSG was retrospectively reviewed. A lifestyle questionnaire, Berlin and Epworth scores, and Patient Health Questionnaire-9 scores were collected. Preoperative anthropometrics, comorbidities, weight loss and body composition outcomes were recorded. RESULTS: Among 208 LSGs, 13 (6.3%) were performed on obese adolescents. Mean age and body mass index (BMI) at first presentation were 19.1 ± 0.9 (range 16.8-19.8) years and 46.2 ± 6.3 (range 36-57) kg/m2, respectively. There was family history of obesity (n = 7) and regular consumption of high-calorie drinks (n = 12). Most patients had comorbidities (n = 12), including hypertension (n = 5), asthma (n = 4), diabetes mellitus (n = 3), hernia (n = 3) and obstructive sleep apnoea requiring continuous positive airway pressure support (n = 3). At one year, excess weight loss was 64.3% ± 34.7% (range 21.8%-101.5%), while BMI and fat mass dropped to 31.2 ± 7.6 (range 23-40) kg/m2 and 17.4 kg, respectively. Pain score was 2/10 at 24 hours after surgery. Mean postoperative stay was 2.7 days. No complications or readmissions occurred. Remission of diabetes mellitus and hypertension was reported in two of three and four of five adolescents, respectively, within one year of surgery. CONCLUSION: LSG is a safe option for adolescents with good short-term weight loss outcomes and remission of metabolic comorbid conditions.

Goal-directed program after sleeve gastrectomy improves weight loss.

BACKGROUND: The aim of our study is to determine if a goal-directed program improves weight loss after sleeve gastrectomy. METHODS: Our goal-directed program involves setting excess weight loss targets at fixed intervals after sleeve gastrectomy. We identified patients in 3 bariatric centers between April 2010 and July 2013 and compared the center that has a goal-directed weight loss program (goal-directed program) with the other 2 centers (standard program). RESULTS: A total of 211 patients were included, with 129 patients in the goal-directed weight loss program. The 2 groups were similar in terms of gender distribution, ethnicity distribution, age, and preoperative weight, preoperative body mass index, and surgical technique. The follow-up rates at 3, 6, 9, and 12 months for patients in the goal-directed program was 84.5%, 75.2%, 59.7%, and 82.2%, respectively, compared with 65.9%, 68.3%, 51.2%, and 68.3% for the standard program. The percentage total weight loss at 3, 6, 9, and 12 months was 17.1%, 23.3%, 26.8%, and 28.6%, respectively, for the goal-directed program, compared with 15.3%, 21.8%, 24.4%, and 25.4%, respectively, for the standard program. The mean excess weight loss at 3, 6, 9, and 12 months were 40%, 54%, 62%, and 67%, respectively, for the goal-directed program group, and 36%, 50%, 54%, and 55%, respectively, for the standard program, where statistical significance (P<.005) was achieved at 12 months. CONCLUSION: Our results suggest that a goal-directed protocol may improve weight loss outcomes after laparoscopic sleeve gastrectomy.