New research from UCLA Health suggests that emotional support within marriages and long-term partnerships may play an important biological role in shaping a person’s weight. The findings highlight how supportive relationships can influence the way the brain and gut communicate, ultimately affecting metabolism, appetite and body mass index (BMI).

Emotional support linked to lower BMI among married adults

Published in Gut Microbes and reported by UCLA Health and StudyFinds, the study found a clear difference among married adults: those who felt genuinely supported by their spouse had lower BMIs and fewer behaviours associated with food addiction.

According to UCLA Health, married individuals with strong emotional support showed BMIs several points lower than those who lacked such support. Interestingly, these patterns did not appear among unmarried participants, suggesting that daily shared routines and long-term partnership dynamics may have a deeper biological influence.

Lead author Dr Arpana Church explained that although social relationships have long been associated with better survival rates, the underlying biological mechanisms were previously unclear. The new findings show that emotional support may reduce obesity risk by influencing internal systems rather than only modifying behaviour.

Brain responses to food shift under supportive relationships

Brain imaging played a central role in the investigation. When married participants with high emotional support viewed images of food, scans revealed stronger activity in the brain region responsible for impulse control, decision-making and cravings management.

This activity was markedly different from what researchers observed in married participants lacking support and in unmarried adults. According to StudyFinds, supportive partnerships may help stabilise the body’s reward circuits, thereby reducing stress-driven eating and strengthening appetite-regulating systems.

Gut microbiome also changes with emotional climate

The study also examined how supportive relationships affect the gut microbiome. Married participants with strong emotional support showed healthier levels of tryptophan metabolites, compounds linked to inflammation control, immune health, energy regulation and mood-related chemicals such as serotonin.

Researchers found that these participants had more beneficial gut compounds and fewer inflammatory markers, suggesting a direct link between social connection and metabolism.

Oxytocin may form the key connection between brain and gut

Oxytocin, often referred to as the bonding hormone, appeared to sit at the centre of these changes. Married individuals generally showed higher oxytocin levels, although not always at statistically significant levels.

Dr Church explained that oxytocin helps coordinate communication between the brain and the gut, allowing the brain to resist cravings while supporting healthy metabolic functions. She added that long-term relationships often require self-control and long-term thinking — the same systems involved in regulating eating behaviour.

A small study, but meaningful implications for public health

The study involved around 100 adults from one region and captured their experiences at a single point in time. Even so, experts say it raises important considerations for obesity research and public health strategies.

As StudyFinds reports, emotional support should be evaluated alongside diet, physical activity and lifestyle when assessing factors that contribute to obesity — a condition affecting more than 40% of American adults.

Dr Church emphasised that emotional connections offer more than psychological comfort. “Social support plays a direct biological role,” she said, noting that strong relationships may help protect long-term physical health.