Reduced Neural Satiety Responses in Women Affected by Obesity

Abstract

Overweight and obesity are major risk factors for a number of chronic diseases, including diabetes, cardiovascular diseases, and cancer. Obesity rates are on the rise worldwide with women more frequently affected than men. Hedonic responses to food seem to play a key role in obesity, but the exact mechanisms and relationships are still poorly understood. In this study, we investigate the perceived pleasantness of food rewards in relation to satiety and calories consumed during an ad libitum meal in women. Using functional magnetic resonance imaging (fMRI) and a milkshake consumption task, we studied how experienced food values are encoded in women with healthy weight, overweight or obesity. Participants rated the pleasantness and intensity of high and low caloric milkshakes in the fMRI scanner during both the fasted and fed states. We found differences in the neural responses and experienced pleasantness of high and low caloric milkshakes depending on satiety and Body Mass Index (BMI). Women with both high ad libitum consumption levels and high BMI reported greater experienced pleasantness for milkshakes. In contrast, among women with low ad libitum consumption levels, greater BMI was associated with less experienced pleasantness. At the neural level, satiety affected women with obesity to a lesser degree than women with healthy weight. Thus, having obesity was associated with altered relationships between food consumption and the hedonic responses to food rewards as well as reduced satiety effects in women.

Genetically-predicted prefrontal DRD4 gene expression modulates differentiated brain responses to food cues in adolescent girls and boys

“…Altered expression of dopamine receptor genes could therefore be associated with dysregulated activity in cortical ensembles, affecting the capacity for cortical inhibition and thereby influencing the functioning of neural circuits underlying food preference and selection related behaviour 50 – 52 . The differentiation of our neuroimaging association results by sex is also broadly consistent with a substantial literature demonstrating sex differences in the rate of structural and functional maturation of prefrontal cortex during adolescence 30 as well as in neural and behavioral responses to food cues 31 , 32 .…”

“…We therefore investigated whether predicted PFC DRD4 expression would be associated with altered brain food cue responsiveness in adolescents. Given known sex differences in brain maturation during adolescence 30 as well as in eating behavior 20 , obesity 23 , and neural responses to food cues 31 , 32 , likely driven by social environment as well as biological factors 25 , we examined relationships in females and males separately. Since obesity is associated with eating in the presence of satiety 33 , and with reduced neural satiety responses 32 , we examined effects of DRD4 PFC expression on neural food cue responses in the satiated/fed, rather than the fasted, state.…”

Is It Worth It? Obesity Affects Snack Food Valuation Across the Menstrual Cycle

“…In addition, diet-induced obesity of female rats is associated with decreased dopamine signaling independent of the menstrual cycle in the nucleus accumbens, which is a fundamental brain region for reward processing ( Geiger et al, 2009 ). We previously analyzed perceived pleasantness of milkshakes in relation to patterns of brain activity detected with fMRI in women with obesity or healthy weight ( Gobbi et al, 2020 ). In that study there was an apparent effect of menstrual cycle phase on perceived pleasantness of sweet milkshakes, but this did not reach statistical significance ( Gobbi et al, 2020 ).…”

“…We previously analyzed perceived pleasantness of milkshakes in relation to patterns of brain activity detected with fMRI in women with obesity or healthy weight ( Gobbi et al, 2020 ). In that study there was an apparent effect of menstrual cycle phase on perceived pleasantness of sweet milkshakes, but this did not reach statistical significance ( Gobbi et al, 2020 ). Here we expand on these findings studying in the same group of women another aspect of appetite, food valuation as an integration of hunger signals, past experience of the food’s flavor and its gastrointestinal and metabolomics effects.…”

Healthy decisions in the cued-attribute food choice paradigm have high test-retest reliability

“…Often in studies using plastic replicas, pictures, or text, participants are asked to make many different food choices with the understanding that one of those choices will be selected to count, where participants will consume the chosen food “for real”. In general, individuals’ choices over food representations such as pictures are associated with aspects of their actual eating behaviors when measured on the same day or in the future and anthropomorphic measures 20 , 21 , 31 , indicating that these paradigms can have a useful degree of ecological and external validity.…”