Reported appetite, taste and smell changes following Roux-en-Y gastric bypass and sleeve gastrectomy: Effect of gender, type 2 diabetes and relationship to post-operative weight loss.

Reduced energy intake drives weight loss following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) procedures. Post-operative changes in subjective appetite, taste, and smell and food preferences are reported and suggested to contribute to reduced energy intake. We aimed to investigate the prevalence of these changes following RYGB and SG and to evaluate their relationship with weight loss. 98 patients post-RYGB and 155 post-SG from a single bariatric centre were recruited to a cross-sectional study. Participants completed a questionnaire, previously utilised in post-operative bariatric patients, to assess the prevalence of post-operative food aversions and subjective changes in appetite, taste and smell. Anthropometric data were collected and percentage weight loss (%WL) was calculated. The relationship between food aversions, changes in appetite, taste and smell and %WL was assessed. The influence of time post-surgery, gender and type 2 diabetes (T2D) were evaluated. Following RYGB and SG the majority of patients reported food aversions (RYGB = 62%, SG = 59%), appetite changes (RYGB = 91%, SG = 91%) and taste changes (RYGB = 64%, SG = 59%). Smell changes were more common post-RYGB than post-SG (RYGB = 41%, SG = 28%, p = 0.039). No temporal effect was observed post-RYGB. In contrast, the prevalence of appetite changes decreased significantly with time following SG. Post-operative appetite changes associated with and predicted higher %WL post-SG but not post-RYGB. Taste changes associated with and predicted higher %WL following RYGB but not post-SG. There was no gender effect post-RYGB. Post-SG taste changes were less common in males (female = 65%, males = 40%, p = 0.008). T2D status in females did not influence post-operative subjective changes. However, in males with T2D, taste changes were less common post-SG than post-RYGB together with lower %WL (RYGB = 27.5 ± 2.7, SG = 14.6 ± 2.1, p = 0.003). Further research is warranted to define the biology underlying these differences and to individualise treatments.

Obesity, body weight regulation and the brain: insights from fMRI.

Obesity constitutes a major global health threat. Despite the success of bariatric surgery in delivering sustainable weight loss and improvement in obesity-related morbidity, effective non-surgical treatments are urgently needed, necessitating an increased understanding of body weight regulation. Neuroimaging studies undertaken in people with healthy weight, overweight, obesity and following bariatric surgery have contributed to identifying the neurophysiological changes seen in obesity and help increase our understanding of the mechanisms driving the favourable eating behaviour changes and sustained weight loss engendered by bariatric surgery. These studies have revealed a key interplay between peripheral metabolic signals, homeostatic and hedonic brain regions and genetics. Findings from brain functional magnetic resonance imaging (fMRI) studies have consistently associated obesity with an increased motivational drive to eat, increased reward responses to food cues and impaired food-related self-control processes. Interestingly, new data link these obesity-associated changes with structural and connectivity changes within the central nervous system. Moreover, emerging data suggest that bariatric surgery leads to neuroplastic recovery. A greater understanding of the interactions between peripheral signals of energy balance, the neural substrates that regulate eating behaviour, the environment and genetics will be key for the development of novel therapeutic strategies for obesity. This review provides an overview of our current understanding of the pathoaetiology of obesity with a focus upon the role that fMRI studies have played in enhancing our understanding of the central regulation of eating behaviour and energy homeostasis.

Obesity Management Task Force of the European Association for the Study of Obesity Released "Practical Recommendations for the Post-Bariatric Surgery Medical Management".

Bariatric patients may face specific clinical problems after surgery, and multidisciplinary long-term follow-up is usually provided in specialized centers. However, physicians, obstetricians, dieticians, nurses, clinical pharmacists, midwives, and physical therapists not specifically trained in bariatric medicine may encounter post-bariatric patients with specific problems in their professional activity. This creates a growing need for dissemination of first level knowledge in the management of bariatric patients. Therefore, the Obesity Management Task Force (OMTF) of the European Association for the Study of Obesity (EASO) decided to produce and disseminate a document containing practical recommendations for the management of post-bariatric patients. The list of practical recommendations included in the EASO/OMTF document is reported in this brief communication.

Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management.

Bariatric surgery is today the most effective long-term therapy for the management of patients with severe obesity, and its use is recommended by the relevant guidelines of the management of obesity in adults. Bariatric surgery is in general safe and effective, but it can cause new clinical problems and is associated with specific diagnostic, preventive and therapeutic needs. For clinicians, the acquisition of special knowledge and skills is required in order to deliver appropriate and effective care to the post-bariatric patient. In the present recommendations, the basic notions needed to provide first-level adequate medical care to post-bariatric patients are summarised. Basic information about nutrition, management of co-morbidities, pregnancy, psychological issues as well as weight regain prevention and management is derived from current evidences and existing guidelines. A short list of clinical practical recommendations is included for each item. It remains clear that referral to a bariatric multidisciplinary centre, preferably the one performing the original procedure, should be considered in case of more complex clinical situations.

Potential Mechanisms Mediating Sustained Weight Loss Following Roux-en-Y Gastric Bypass and Sleeve Gastrectomy.

Bariatric surgery is the only effective treatment for severe obesity. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), the most commonly performed procedures, lead to sustained weight loss, improvements in obesity-related comorbidities and reduced mortality. In humans, the main driver for weight loss following RYGB and SG is reduced energy intake. Reduced appetite, changes in subjective taste and food preference, and altered neural response to food cues are thought to drive altered eating behavior. The biological mediators underlying these changes remain incompletely understood but changes in gut-derived signals, as a consequence of altered nutrient and/or biliary flow, are key candidates.