Link between Impulsivity and Overeating: Psychological and Neurobiological Perspectives

In most basic terms impulsivity is defined as a tendency to act without control. Impulsivity has been implicated in the onset, symptomatic expression, and maintenance of overeating. Specifically, high impulsivity and associated poor inhibitory control, along with sensation seeking and reward sensitivity, as well as negative affect have been found to have an interaction effect on emotional eating, which may lead to binge eating and obesity. Moreover, associations between overeating and impulsive behaviors such as difficulty in response inhibition, planning, attention, addiction, or risk taking etc. have been previously shown. The purpose of this review is to summarize the evidence from psychology regarding the potential role of the impulsivity trait in overeating, with implications on the treatments for obesity and binge eating

Evaluation of CSF and plasma biomarkers of brain melanocortin activity in response to caloric restriction in humans

The melanocortin neuronal system, which consists of hypothalamic proopiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, is a leptin target that regulates energy balance and metabolism, but studies in humans are limited by a lack of reliable biomarkers to assess brain melanocortin activity. The objective of this study was to measure the POMC prohormone and its processed peptide, β-endorphin (β-EP), in cerebrospinal fluid (CSF) and AgRP in CSF and plasma after calorie restriction to validate their utility as biomarkers of brain melanocortin activity. CSF and plasma were obtained from 10 lean and obese subjects after fasting (40 h) and refeeding (24 h), and from 8 obese subjects before and after 6 wk of dieting (800 kcal/day) to assess changes in neuropeptide and hormone levels. After fasting, plasma leptin decreased to 35%, and AgRP increased to 153% of baseline. During refeeding, AgRP declined as leptin increased; CSF β-EP increased, but POMC did not change. Relative changes in plasma and CSF leptin were blunted in obese subjects. After dieting, plasma and CSF leptin decreased to 46% and 70% of baseline, CSF POMC and β-EP decreased, and plasma AgRP increased. At baseline, AgRP correlated negatively with insulin and homeostasis model assessment (HOMA-IR), and positively with the Matsuda index. Thus, following chronic calorie restriction, POMC and β-EP declined in CSF, whereas acutely, only β-EP changed. Plasma AgRP, however, increased after both acute and chronic calorie restriction. These results support the use of CSF POMC and plasma AgRP as biomarkers of hypothalamic melanocortin activity and provide evidence linking AgRP to insulin sensitivity

Gastrointestinal hormones and roux-en-y gastric bypass

Obesity is a multifactorial global epidemic with associated risk factors for an array of vascular, metabolic, psychological and economical consequences. Bariatric surgery offers the most effective results and Roux-en-Y gastric bypass (RYGB) is the most commonly performed bariatric surgery worldwide. The effective weight loss achieved by RYGB is thought to be caused by the re-arrangement of the gastrointestinal tract leading malabsorption and restriction of the ingested nutrients, and consequently resulting in alterations in the gut hormone levels. This review briefly summarizes the current literature on the changes in the gastrointestinal hormones following RYGB. Understanding these post-operative alterations may provide insights on the efficacy of RYGB that may help developing superior surgical techniques, novel pharmacological and psychological interventions, as well as prevention strategies against obesity

Gastrointestinal hormones and roux-en-y gastric bypass

Obesity is a multifactorial global epidemic with associated risk factors for an array of vascular, metabolic, psychological and economical consequences. Bariatric surgery offers the most effective results and Roux-en- Y gastric bypass (RYGB) is the most commonly performed bariatric surgery worldwide. The effective weight loss achieved by RYGB is thought to be caused by the re-arrangement of the gastrointestinal tract leading malabsorption and restriction of the ingested nutrients, and consequently resulting in alterations in the gut hormone levels. This review briefly summarizes the current literature on the changes in the gastrointestinal hormones following RYGB. Understanding these post-operative alterations may provide insights on the efficacy of RYGB that may help developing superior surgical techniques, novel pharmacological and psychological interventions, as well as prevention strategies against obesity

Structural and Functional Neural Correlates of Anorexia Nervosa

The findings from neuroscience have shaped our understanding in the past decade regarding the way we perceive psychiatric illness. In addition to the more conventional theories that are based solely on the psychological and sociocultural factors to explain psychiatric disorders, there is growing evidence supporting a multifactorial etiology with genetic and neurological components. Anorexia nervosa, a life-threatening psychiatric disorder with relentless restrictive eating resulting in extremely low body weight, is one such illness that may be categorized as a brain disorder based on the recent findings. Although inconsistencies exist, several studies investigated the structural and the neurochemical alterations in the brain as well as the functional significance and the cognitive manifestations of these abnormalities in anorexia nervosa patient. This review aims to summarize the current literature on the neural aberrations and several treatment approaches targeting these abnormalities in anorexia nervosa

A COMMON GENETIC ETIOLOGY FOR IMPULSIVITY AND OVEREATING

10.3153/fh18024Food and Health44247-25