Differences in the neuronal response to food in obesity-resistant as compared to obesity-prone individuals

Abstract

Despite living in an obesogenic environment, some individuals maintain a thin phenotype compared to the majority who are at risk for weight gain and obesity. Understanding how these different phenotypes regulate energy intake is critical. The objective of this study was to examine the differences in neuronal response to visual food cues in adults recruited as either obesity-resistant (OR) or obesity-prone (OP) based on self-identification, BMI, and personal/family weight history. 25 OR and 28 OP individuals were studied after 4 days of eucaloric energy intake. Functional magnetic resonance imaging (fMRI) was performed in the fasted and acute fed states (30 minutes after a test meal) while subjects viewed images of foods of high hedonic value and neutral non-food objects. Measures of appetite using visual analog scales were performed before and every 30 minutes after the test meal for 3 hours. In the fasted state, food as compared to nonfood images elicited significant response in the insula, somatosensory cortex, parietal cortex, and visual cortex in both OR and OP. The acute fed state resulted in significant attenuation of these and other brain areas in the OR but not OP individuals. Furthermore, OP as compared to OR individuals showed greater activation of medial and anterior prefrontal cortex (PFC) in response to the test meal. Adjusting for fat mass did not impact these results. Attenuation of insula/PFC response to food images in the fed state was associated with greater reductions in hunger. These findings suggest that individuals prone to weight gain and obesity have altered neuronal responses to food cues in brain regions known to be important in energy intake regulation. These altered responses may represent an important mechanism contributing to excess energy intake and risk for obesity.

The way to her heart? Response to romantic cues is dependent on hunger state and dieting history: An fMRI pilot study

“…As addressed above, these constructs may be related, but historical dieting is a much more robust predictor of future weight gain (Lowe et al, 2013). However, despite these differences, our findings are consistent with research utilizing different measures of obesity-proneness that demonstrate differential responsivity of reward regions to visual food cues (Coletta et al, 2009;Cornier et al, 2013;Demos et al, 2011;Ely et al, 2014) and that these alterations in neural activity predict future weight gain (Burger & Stice, 2014;Demos et al, 2012). Given these findings, romantic images represent an important category of reward that had yet to be explored in this population.…”

“…A recent study (Ely et al, 2014), found that historical dieters (HDs), showed greater response to highly palatable food cues than non-dieters (NDs) when satiated in the dorsal anterior cingulate cortex and middle frontal gyrus. This is consistent with other research that demonstrates differential activation when nutritionally sated in individuals at risk for obesity (Cornier et al, 2013(Cornier et al, , 2015 and those high in dietary restraint (Coletta et al, 2009). It is clear that neurobiological differences in the processing of food reward exist in young women prior to the manifestation of weight gain (Lowe et al, 2013).…”

“…Goldstone et al, 2009) Past research suggests that neurobiological sensitivity to food reward specific to the fed state exists in normal weight dieters (Ely et al, 2014) and obese-prone populations (Cornier et al, 2013), that eventually may lead to weight gain (Burger & Stice, 2014; Demos , 2011), consistent with our conceptualization of dieting behavior as indicative of a predisposition toward positive energy balance and eventual weight gain (Lowe & Butryn, 2007;Lowe et al, 2013;Wadden et al, 2004). This exploratory study of more broadly-based positive stimuli indicates that there may be neurally-based sensitivities to reward beyond food that is modulated by satiation in those both with and without a history of dieting, and particularly in HDs in the middle temporal gyrus.…”

Functional brain imaging and its application to uncover mechanisms driving food intake in humans

“…Accordingly, in more recent studies [6,68] an irregular activation in a range of regions involved in hedonic food intake has been observed, which suggests an increased central sensitivity to palatable food in obese individuals.…”

“…The resulting motivation for food intake is thus considered principally driven by the reward value of foods which overrides internal signals of satiety and gives rise to the development of a separate motivation to consume palatable foods mainly for their hedonic appeal, under the urge of the so-called hedonic hunger [1][2][3] . Rapid societal changes in relation to food availability and consumption, driven mainly by gustatory properties rather than energy content, are being increasingly recognised as strongly contributing to the recent surge of obesity and its associated co morbidities worldwide [5,6] .…”