The study found that people who feel emotionally supported and are married tend to have lower body weight, healthier eating habits, higher blood oxytocin, and brain and gut changes that curb cravings and inflammation. In simple terms, good relationships may boost oxytocin naturally and help keep weight down.

Social relationships play a crucial role in shaping health. To better understand the underlying mechanisms, we explored the independent and interactive effects of perceived emotional support (PES) and marital status on body mass index (BMI), eating behaviors, brain reactivity to food images, plasma oxytocin, and alterations in the brain-gut microbiome (BGM) system. Brain responses to food stimuli, fecal metabolites, and plasma oxytocin levels were measured in 94 participants. Structural equation modeling was used to determine the integrated pathways linking social factors to obesity-related outcomes. Marital status and PES interact and independently influence lower BMI, healthier eating behaviors, increased oxytocin levels, food-cue reactivity in frontal brain regions involved in craving inhibition and executive control, and tryptophan-pathway metabolites related to inflammation, immune regulation, and energy homeostasis. These findings suggest that supportive human relationships, particularly high-quality marital bonds, may regulate obesity risk through oxytocin-mediated alterations in brain and gut pathways.