Social Isolation, Food Signal Processing in the Brain, Eating Behaviors, and Mental Health Symptoms
Is perceived social isolation associated with brain reactivity to food signals, obesity, and psychological symptoms?
In this cross-sectional study of 93 healthy premenopausal female participants, social isolation was linked to altered brain processing of food signals in the default mode, executive control, and visual attention networks. These neural changes (particularly in response to sweet foods) showed an association between social isolation, eating behaviors, and psychological symptoms.
These findings suggest that increased loneliness may be related to brain patterns that highlight difficulties in motivation, control, and processing of internal states in response to food. This can lead to greater disruptions in eating behaviors, obesity, and psychological symptoms, suggesting future targets for obesity treatments.
Figure: Comparisons of whole-brain activity between high and low perceived isolation groups. Warm-colored areas (red) indicate greater reactivity in the high perceived isolation group than in the low perceived isolation group. Cool-colored areas (blue) indicate greater reactivity in the low perceived isolation group than in the high perceived isolation group. Results of the comparison are adjusted for age. Family-wise error correction: z-score above 2.3 (p < 0.05).
A new study from UCLA Health has found that women who perceive themselves as lonely exhibit activity in brain regions associated with cravings and motivation to eat, especially when shown images of high-calorie foods like sugary treats. This same group of women also demonstrated unhealthy eating behaviors and poor mental health.
Arpana Gupta, PhD, a researcher and co-director of UCLA’s Goodman-Luskin Microbiome Center, sought to investigate the negative impacts of loneliness, particularly as people continue to work remotely after the COVID-19 pandemic, and how the brain interacts with social isolation, eating habits, and mental health. While it’s established that obesity is linked to depression and anxiety, and binge eating is understood as a coping mechanism for loneliness, Gupta wanted to examine the brain pathways associated with these feelings and behaviors.
“How the brain processes loneliness and how it relates to obesity and health outcomes has not been investigated,” said Gupta, the lead author of the paper, which was published in JAMA Network Open.
Researchers surveyed 93 women about their support systems and feelings of loneliness and isolation, then divided them into two groups: those who scored high on the perceived social isolation scale and those who scored low. Researchers found that women with higher levels of social isolation tended to have higher body fat mass, lower diet quality, increased cravings, reward-based eating, uncontrolled eating, and higher levels of anxiety and depression.
The women were then shown images of food versus non-food items, sweet versus non-food items, and salty versus non-food items. MRI images recorded participants’ brain activity while viewing these images.
Researchers found that the group of women who perceived themselves as lonely experienced greater activation in brain regions associated with stronger cravings for sugary foods and less activation in the brain region associated with self-control over eating behaviors.
“These findings are interesting because they provide evidence for what we intuitively know,” Gupta said. “When people are lonely, it affects more than just how they feel; it impacts their food choices, desire to eat, and cravings, especially for unhealthy foods.”
“If you have more cravings, you eat more, and you may experience more anxiety or depression, which can lead to more eating,” said Xiaobei Zhang, postdoctoral researcher and lead author, comparing this pathway to a “vicious cycle between unhealthy eating and negative mental symptoms.”
Researchers suggested that holistic mind-body interventions could break this cycle. Examples include being mindful of feeling lonely and, depending on the person, seeking connection with others or practicing self-compassion. Another suggestion is to opt for healthier food choices. “Instead of consuming that highly addictive, sweet, high-calorie food you crave, maybe try choosing healthier options instead,” said Gupta.
Gupta’s future research will focus on exploring other biological markers such as metabolites, the microbiome, and inflammatory signatures associated with loneliness.
These findings suggest that social isolation is linked to altered neural reactivity to food signals in specific brain regions responsible for processing internal appetite-related states, impaired executive control, and a bias in attention and motivation toward external food signals. These neural responses to specific foods were associated with a higher risk of increased body fat composition, worsening maladaptive eating behaviors, and compromised mental health. These findings underscore the need for holistic mind-body interventions to mitigate the adverse health effects of social isolation.
