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

Abstract

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.

The role of appetite-related hormones, adaptive thermogenesis, perceived hunger and stress in long-term weight-loss maintenance: a mixed-methods study

“…Our findings are consistent with evidence from bariatric surgery studies, reporting that poorer long-term weight loss maintenance outcomes are associated with attenuated GLP-1 response (36). GLP-1 infusion enhances satiety and reduces energy intake (37) and brain imaging studies have demonstrated that higher GLP-1 concentration diminishes the reward value of food (38,39). GLP-1 analogue therapy is associated with improved weight loss maintenance (40) and identifying individuals with low concentrations of GLP-1 may help to establish who is likely to respond well or poorly to a weight loss intervention (41) and facilitate targeted treatments, with non-pharmalogical approaches to increase endogenous GLP-1 now under study (42).…”

Predictors of a Healthy Eating Disorder Examination-Questionnaire (EDE-Q) Score 1 Year After Bariatric Surgery

“…Despite its limitations, this study has several important strengths, particularly the complete 1year follow-up in a relatively large BS patient cohort that received standardized singleinstitutional perioperative care. The pathways that link the postbariatric neurophysiologic changes and the improvements in eating behavior are currently not entirely understood [36,37,39,44,45]. The presented findings might generate further hypotheses on the amelioration of eating behavior after BS and may foster the design of future studies, including assessment of "signature" postbariatric eating disorders [46] and direct measurement of pre-and postoperative food intake [47].…”

Relationship Between Fat Mass and Obesity-Associated (FTO) Gene Polymorphisms with Obesity and Metabolic Syndrome in Ethnic Mongolians

“…With increased incidence, obesity has become a global public health problem. Obesity is associated with several diseases, such as diabetes, hypertension, hyperlipidemia, and cardiovascular and cerebrovascular diseases [ 17 , 18 ]. In this study, the body weight, BMI, WC, HC, WHR, SBP, DBP, FPG, TG, TC, and LDL-C were higher, while HDL-C was lower in the obesity group compared with controls, confirming its role in the pathogenesis of obesity.…”