Researchers are studying how stress can increase appetite in obese and lean adults

Researchers are studying how stress can increase appetite in obese and lean adults

In a series of experiments using functional magnetic resonance imaging (fMRI) to measure brain activity across networks in the brain, researchers at Johns Hopkins Medicine examined how stress can increase appetite in obese and lean adults. The researchers found that stress affects the brain's responses to food and that both lean and obese adults respond to food signals in areas of the brain associated with reward and cognitive control.

The results of the study were published September 28 in PLOS ONE.

For the study, researchers analyzed data from 29 adults (16 women and 13 men), 17 of whom were obese and 12 of whom were slim. Participants completed two fMRI scans, one after a combined social and physiological stress test.

During both scans, participants underwent a food word reactivity test. This test examined how people's brains responded to food words, such as menu items on a blackboard. To maximize the brain's appetite response, researchers asked participants to imagine what each food looked, smelled, and tasted like, and what it would feel like to eat it at that moment. They were also asked how much they wanted each food and whether they thought they shouldn't eat that food to see how they went about making decisions about each food.

The experiments showed that obese and lean adults differ somewhat in their brain responses, with obese adults showing less activation of cognitive control regions to food words, particularly to high-calorie foods, such as grilled cheese.

Susan Carnell, Ph.D., senior researcher, associate professor of psychiatry and behavioral sciences, Johns Hopkins University School of Medicine

The study also showed that stress affects brain responses to food. For example, overweight people showed greater activation of the orbitofrontal cortex, a reward region in the brain, after the stress test. "We also found evidence of associations between the subjective stress experienced and brain responses in both groups. For example, lean individuals who reported higher stress after the test showed lower activation in the dorsolateral prefrontal cortex, an important brain area for cognitive control," says Carnell.

Source:

Johns Hopkins Medicine

Reference:

Carnell, S., et al. (2022) Obesity and acute stress modulate appetite and neural responses in the food word reactivity task. PLUS ONE. doi.org/10.1371/journal.pone.0271915.

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