Eating a meal in the company of someone close may do more than provide emotional comfort.
New research from the Hebrew University of Jerusalem and Sheba Medical Center suggests that social closeness may help the body regulate blood glucose more efficiently after eating.
The researchers found that participants experienced smaller post-meal blood-sugar increases and faster recovery when they ate in a social setting compared with eating alone, despite consuming the same standardized carbohydrate meal.
The findings, published in Science Advances under the title “Social Physiology: Human homeostasis is more efficient in social proximity,” introduce what the researchers describe as “social physiology” — the idea that the human body may regulate fundamental physiological processes more efficiently when people are close to trusted social partners.
The study was led by Hebrew University professor Shir Atzil and PhD researcher Monia Masalha, together with Dr. Shai Fuchs of Sheba Medical Center. The research team spent about three years conducting the project.
“We used to think of the body as an isolated system that regulates itself,” Atzil told The Jerusalem Post.
“Our findings show that human physiology is inherently social. Being close to someone you love lowers the physical energy your body spends on regulating itself. This gives us a direct metabolic benefit to being together and reveals a core evolutionary reason why humans form bonds in the first place: our bodies run better together.”
A biological effect of social connection
Previous research has established that people who live or work closely together can develop similarities in daily routines, including sleep patterns, exposure to light, screen use and meal schedules. Emotional states can also appear to spread among people who share close environments.
The Hebrew University study examined whether such interpersonal connections could extend to basic physiological regulation.
Participants underwent a standardized meal test involving 50 grams of carbohydrates delivered through 102 grams of standardized white-wheat bread. Researchers then monitored their blood glucose levels for two hours.
According to the research team, glucose regulation was more efficient when participants were in the presence of a socially close person. The average change in glucose levels was reported at 23%, although the magnitude of the effect varied considerably between individuals.
“The average change in the glucose level was 23%. “Overall, it was a significant effect, but there was a huge variation. Some had a big benefit, while others had much less. I can’t say now what caused the differences,” she continued.
The researchers said the effect was not limited to blood glucose. Their experiments also indicated that social proximity could influence temperature regulation during exposure to cold and reduce stress responses in both adults and infants.
Importantly, the reported physiological benefits did not depend on physical contact and could not be explained simply by lower stress levels.
Why does companionship affect the body?
Atzil said the researchers believe the brain could play a central role in the phenomenon.
“I think it’s the brain, whose most important job is to keep the body up and running. A baby is dependent on caregivers and can’t eat by themselves.
“Gradually, as they grow older, their brains develop with close human bonds. It doesn’t even have to be its parents. Anybody who takes care of an infant with sensitivity and a positive input affects the baby, who learns to regulate its body through social interaction.”
The findings also raise questions about why humans and other social species devote so much energy to maintaining relationships.
In their paper, the researchers argued that existing theories of attachment and social neuroscience explain important aspects of human relationships but leave a broader evolutionary question: why do social animals invest substantial physical and mental resources in social interaction despite the possibility of conflict, competition and other costs?
“This discovery has two key implications; the first concerns evolution. Although attachment theory and social neuroscience have provided valuable insights into how close relationships are formed and maintained, they don’t resolve a central paradox.
“Why are social animals motivated to invest considerable cognitive and physical effort, and accept risks of competition, conflict, and aggression to engage in social interactions?… Addressing this discrepancy requires identifying immediate gains that make social interaction worthwhile in the moment yet can also accumulate into long-term fitness benefits.”
Atzil said the physiological effect identified by the team represents a previously unexplored aspect of social interaction.
“What we discovered was not known at all. Nobody else has studied it.”
Physical touch was not necessary
The experiments were conducted in a laboratory room designed to resemble a living room. Participants were connected to monitoring equipment but were not required to sit together at a table or follow a specific interaction pattern.
“For the experiments, we used a room in our lab that looks like a living room. They were all connected to electrodes. They didn’t have to sit together at a table. We let them do whatever they wanted,” recalled Atzil. “I thought touch would be a strong indicator, but it wasn’t.”
The researchers accounted for a range of factors that could potentially affect glucose regulation, including age, sex, body-mass index, metabolic health, stress and the amount of physical contact between participants.
“There were no differences between men and women. We controlled for age, gender, body-mass index, metabolic health, how much they touched, stress levels, and more. We looked for strongest-connection partners and mothers and children.
“The study is preliminary, and there is a lot more to learn. Our next step will be to study siblings and strangers.”
The researchers also observed substantial variation among individuals, meaning the physiological response to social proximity was not uniform.
Potential implications for people who eat alone
The findings could eventually have relevance to groups for whom social isolation or solitary meals are common, including older adults, hospital patients and people living in residential care. However, the researchers stressed that those possibilities require further investigation.
The team has not yet tested whether the same response occurs in people with diabetes or prediabetes.
Atzil described that research direction as “the obvious direction of our research.”
Asked whether the findings might have implications for older people who regularly eat alone, hospital patients, people living by themselves or nursing-home residents, she said: “it could be if social physiology has a real effect. It should be studied.”
The researchers cautioned that the study does not establish that companionship can prevent or treat diabetes, nor does it replace established approaches such as appropriate nutrition, physical activity and medical treatment.
Instead, the findings point to social connection as a potentially important factor in understanding how the body responds to everyday experiences such as eating.
“Blood sugar regulation is not just about what we eat, but who we eat with,” says Atzil. “Our relationships have an active biological role in our physical wellbeing.”
A developing field of research
The research was supported by a European Research Council Starting Grant awarded to Atzil. She heads the Bonding Neuroscience Laboratory at the Hebrew University, where her work focuses on the neural and behavioral mechanisms involved in forming and maintaining close relationships.
The researchers say their current results provide evidence for a broader principle in human physiology, but they acknowledge that much remains unknown about the mechanism, the people most affected and whether the findings apply across different types of relationships and health conditions.
“We still have a lot of questions, but its significance among our participants makes us believe the effect. We still have to characterize it much more to discover how generalizable it is.”
For now, the study adds a new dimension to research into human relationships: companionship may not only influence how people feel, but may also interact with the body’s fundamental systems of regulation.
