Neuroimaging of Sex/Gender Differences in Obesity: A Review of Structure, Function, and Neurotransmission

Abstract

While the global prevalence of obesity has risen among both men and women over the past 40 years, obesity has consistently been more prevalent among women relative to men. Neuroimaging studies have highlighted several potential mechanisms underlying an individual’s propensity to become obese, including sex/gender differences. Obesity has been associated with structural, functional, and chemical alterations throughout the brain. Whereas changes in somatosensory regions appear to be associated with obesity in men, reward regions appear to have greater involvement in obesity among women than men. Sex/gender differences have also been observed in the neural response to taste among people with obesity. A more thorough understanding of these neural and behavioral differences will allow for more tailored interventions, including diet suggestions, for the prevention and treatment of obesity.

Differentially Expressed Genes and Enriched Signaling Pathways in the Adipose Tissue of Obese People

“…Therefore, it is important to explore gene expression changes and associated molecular mechanisms in the adipose tissue of obese individuals. As the different estrogen levels and neural underpinnings affect body adipose tissue levels and appetite, obesity rates are higher in women than in men in most countries and regions, with an average prevalence of 10 and 18% in men and women, respectively ( Kroll et al, 2020 ). Because of this, many studies have examined male and female obesity separately ( Garawi et al, 2014 ).…”

Structural Brain Changes Associated with Overweight and Obesity

“…In men, total body fat is negatively correlated with all subcortical gray matter volumes (thalamus, caudate nucleus, putamen, globus pallidus, and nucleus accumbens); in women, a greater total body fat is correlated with lower globus pallidus volume [94]. ese sex-specific differences may be explained by several endocrine pathways; for instance, estrogens act as a protective factor against many metabolic complications related to obesity [95].…”

Inter-Individual Differences in Food Addiction and Other Forms of Addictive-Like Eating Behavior

“…These seven original studies investigate the factors associated with this phenotype in different contexts: patients seeking treatment for an eating disorder, including anorexia nervosa, bulimia nervosa or binge eating disorder [ 12 , 13 ], patients seeking treatment for obesity (i.e., bariatric surgery candidates) [ 14 ], and non-clinical populations (i.e., persons not directly seeking treatment for these conditions) such as adolescents [ 15 ], female restrained eaters [ 16 ], and persons with weight-related disorders recruited in the general population [ 17 ]. This special issue also present four literature reviews that focus on: neuroimaging of sex/gender differences in obesity, in which FA is prevalent [ 18 ], involvement of the melanocortin system in binge eating, food reward and motivation [ 19 ], association between addictive-like eating behavior and attention-deficit/hyperactivity disorder (ADHD) [ 20 ], and a discussion about the FA concept and its practical implications through four complementary disciplines: addiction medicine, nutrition, health psychology, and behavioral neuroscience [ 21 ].…”

“…When studying the inter-individual differences, gender/sex may be an important factor to consider. In an elegant literature review, Kroll et al shed light on the neuroimaging of sex/gender differences in persons with obesity, with a focus on structure, function, and neurotransmission [ 18 ]. They highlighted inter-individual differences based on gender: changes in somatosensory regions appeared to be associated with obesity in men, while changes in reward regions were more strongly associated with obesity in women than in men.…”