American association of clinical endocrinologists and american college of endocrinology comprehensive clinical practice guidelines for medical care of patients with obesity.

Emotion regulation model in binge eating disorder and obesity--a systematic review.

The gut harbors an enormous diversity of microbes that are essential for the maintenance of homeostasis in health and disease. A growing body of evidence supports the role of this microbiota in influencing host appetite and food intake. Individual species within the gut microbiota are under selective pressure arising from nutrients available and other bacterial species present. Each bacterial species within the gut aims to increase its own fitness, habitat, and survival via specific fermentation of dietary nutrients and secretion of metabolites, many of which can influence host appetite and eating behavior by directly affecting nutrient sensing and appetite and satiety-regulating systems. These include microbiota-produced neuroactives and short-chain fatty acids. In addition, the gut microbiota is able to manipulate intestinal barrier function, interact with bile acid metabolism, modulate the immune system, and influence host antigen production, thus indirectly affecting eating behavior. A growing body of evidence indicates that there is a crucial role for the microbiota in regulating different aspects of eating-related behavior, as well as behavioral comorbidities of eating and metabolic disorders. The importance of intestinal microbiota composition has now been shown in obesity, anorexia nervosa, and forms of severe acute malnutrition. Understanding the mechanisms in which the gut microbiota can influence host appetite and metabolism will provide a better understanding of conditions wherein appetite is dysregulated, such as obesity and other metabolic or eating disorders, leading to novel biotherapeutic strategies.

Microbiota-Gut-Brain Axis: Modulator of Host Metabolism and Appetite.

Inhibitory control in obesity and binge eating disorder: A systematic review and meta-analysis of neurocognitive and neuroimaging studies

Objectives Roux-en-Y gastric bypass (RYGB) has greater efficacy for weight loss in obese patients than gastric banding (BAND) surgery. We hypothesise that this may result from different effects on food hedonics via physiological changes secondary to distinct gut anatomy manipulations. Design We used functional MRI, eating behaviour and hormonal phenotyping to compare body mass index (BMI)-matched unoperated controls and patients after RYGB and BAND surgery for obesity. Results Obese patients after RYGB had lower brain-hedonic responses to food than patients after BAND surgery. RYGB patients had lower activation than BAND patients in brain reward systems, particularly to high-calorie foods, including the orbitofrontal cortex, amygdala, caudate nucleus, nucleus accumbens and hippocampus. This was associated with lower palatability and appeal of high-calorie foods and healthier eating behaviour, including less fat intake, in RYGB compared with BAND patients and/or BMI-matched unoperated controls. These differences were not explicable by differences in hunger or psychological traits between the surgical groups, but anorexigenic plasma gut hormones (GLP-1 and PYY), plasma bile acids and symptoms of dumping syndrome were increased in RYGB patients. Conclusions The identification of these differences in food hedonic responses as a result of altered gut anatomy/physiology provides a novel explanation for the more favourable long-term weight loss seen after RYGB than after BAND surgery, highlighting the importance of the gut–brain axis in the control of reward-based eating behaviour.

https://gut.bmj.com/content/gutjnl/63/6/891.full.pdf

Obese patients after gastric bypass surgery have lower brain-hedonic responses to food than after gastric banding

Impulsivity towards food has been recognized as a potential factor leading to increased food intake in obesity. Patients suffering from binge eating disorder (BED) form a specific subgroup of obese people that might be characterized by increased impulsivity. These assumptions, although, have yet to be verified. Therefore, this review evaluates evidence for food-related impulsivity in obese people with and without BED and examines possible differences between both populations. More precisely, evidence for the two components of impulsivity is analyzed separately: evidence for reward sensitivity, specifically, the urge for appetitive stimuli and evidence for rash-spontaneous behaviour such as acting disinhibited with no regard for the consequences. Our search resulted in 51 articles demonstrating generally increased food-related impulsivity. We found particular emphasis on increased reward sensitivity in obese people, which appeared to be more pronounced in people with BED. There was little and conflicting evidence, however, concerning increased rash-spontaneous behaviour in obese people without BED, but consistent evidence of an increase in obese people with BED. All in all, the evidence supports the view that BED represents a specific phenotype of obesity with increased food-related impulsivity. Taking these specific deficits into account can enhance the effectiveness of weight reduction programmes and psychotherapy.

J. Schönleber

Papers

Food‐related impulsivity in obesity and Binge Eating Disorder – a systematic review