A Comparison of Total Food Intake at a Personalised Buffet in People with Obesity, before and 24 Months after Roux-en-Y-Gastric Bypass Surgery.

Long-term reductions in the quantity of food consumed, and a shift in intake away from energy dense foods have both been implicated in the potent bariatric effects of Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised that relative to pre-operative assessment, a stereotypical shift to lower intake would be observed at a personalised ad libitum buffet meal 24 months after RYGB, driven in part by decreased selection of high energy density items. At pre-operative baseline, participants (n = 14) rated their preference for 72 individual food items, each of these mapping to one of six categories encompassing high and low-fat choices in combination with sugar, complex carbohydrate or and protein. An 18-item buffet meal was created for each participant based on expressed preferences. Overall energy intake was reduced on average by 60% at the 24-month buffet meal. Reductions in intake were seen across all six food categories. Decreases in the overall intake of all individual macronutrient groups were marked and were generally proportional to reductions in total caloric intake. Patterns of preference and intake, both at baseline and at follow-up appear more idiosyncratic than has been previously suggested by verbal reporting. The data emphasise the consistency with which reductions in ad libitum food intake occur as a sequel of RYGB, this being maintained in the setting of a self-selected ad libitum buffet meal. Exploratory analysis of the data also supports prior reports of a possible relative increase in the proportional intake of protein after RYGB.

Fat free mass is positively associated with hunger and energy intake at extremes of obesity.

Fat mass (FM) has been shown to be negatively associated with energy intake (EI) in lean individuals but in overweight and Class I obese individuals this relationship is poorly understood. Fat free mass (FFM) is positively associated with EI in lean, overweight and Class I obese individuals. To date, the relationships between FFM, FM, hunger and EI have not been investigated in patients with a body mass index (BMI) > 35 kg/m2. The aim of the present study was to examine the associations between FFM, FM, BMI, hunger and EI in individuals with severe (BMI > 35 kg/m2) obesity. In total, 43 subjects (52% male) with a mean (±standard deviation) BMI of 44.5 ±â€¯6.2 kg/m2 were recruited for this cross-sectional analysis. Dual energy x-ray absorptiometry and an ad libitum food buffet were used to measure body composition and EI respectively, and hunger was measured using a visual analogue scale (0-100 mm). BMI (p = 0.02; p < 0.01) and FFM (p < 0.01; p = 0.02), but not FM (p = 0.18; p = 0.71), were positively associated with both EI and pre-buffet hunger, respectively, on multivariable regression using the general linear model. These findings suggest that in extremes of obesity FFM continues to promote hunger and EI, but the inhibitory effect of FM on EI that has been observed in lean populations was not present in this cohort suffering from severe obesity.

Proceedings from the 2018 Association for Chemoreception Annual Meeting Symposium: Bariatric Surgery and Its Effects on Taste and Food Selection.

This article provides a summary of the topics discussed at the symposium titled "Bariatric Surgery and Its Effects on Taste and Food Selection," which was held at the Fortieth Annual Meeting of the Association for Chemoreception Sciences. Bariatric surgery such as Roux-en-Y gastric bypass (RYGB) is currently one of the most effective treatments available for weight loss and Type 2 diabetes. For this reason, it is of great interest to clinicians as well as to basic scientists studying the controls of feeding and energy balance. Despite the commonly held view by clinicians that RYGB patients change their food preferences away from fats and sugars in favor of less energy dense alternatives such as vegetables, the empirical support for this claim is equivocal. It is currently thought that the taste and palatability of fats and sugars are affected by the surgery. Some key preclinical and clinical findings addressing these issues were evaluated in this symposium.

Shifts in Food Preferences After Bariatric Surgery: Observational Reports and Proposed Mechanisms.

PURPOSE OF REVIEW: Bariatric surgery is currently the most effective treatment for obesity. Roux-en-Y gastric bypass (RYGB) is the most commonly performed bariatric procedure and results in long-term weight loss. Alterations in food preference and choices may contribute to the long-term benefits of RYGB. This manuscript reviews the available literature documenting changes in food preference in both humans and experimental animals after RYGB and discusses the current theory on the underlying mechanisms involved. RECENT FINDINGS: Obesity is associated with an increased preference for sweet and high-fat foods, and the most consistent evidence has been the shift away from these calorie-dense foods in both animal and human studies after RYGB. Self-reporting is the most common method used to record food preferences in humans, while more direct approaches have been used in animal work. This methodological heterogeneity may give rise to inconsistent findings. Future studies in humans should focus on direct measures to permit corroboration of mechanistic insights gained from animal studies.