Obese people are more likely to exhibit unhealthy food decisions when sated

Food decision-making plays a key role in weight loss and obesity prevention. It involves the value and integration of food attributes, such as health and taste. However, how homeostatic status affects the value and integration of food attributes, especially in obese people, remains unknown. To address this question, we investigated how metabolic states (sated vs. fasting) may affect food decision-making and brain response. This study encompassed a multifaceted approach, investigating hormone levels, decision-making processes relating to food, and fNIRS data. We recruited 20 obese and 20 normal-weight subjects. We found that there were no differences between obese and normal weights in health and taste ratings. However, the weight of health ratings was higher in sated normal weight people than sated obese people. The dlPFC activity showed a similar pattern with the weight of health ratings. The functional connectivity between the vmPFC and dlPFC was lower in obese people when sated than during fasting, while this connectivity remained relatively constant in counterparts. Sated normal weight people had stronger associations between ghrelin levels and the dlPFC activation than sated obese people. Our results highlight the role of the dlPFC with regard to the homeostatic signaling regulation of food decision-making and suggest that obese people are more likely to exhibit unhealthy eating behavior when sated, which may be related to the reduced ability of the dlPFC to downregulate the vmPFC.