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Can Obesity and Stress Affect Appetite?

Summary: Researchers reported that stress affects the brain’s response to food. Additionally, both lean and obese people respond to food cues in brain regions associated with reward and cognitive control.

Source: Johns Hopkins Medicine

In a series of experiments using functional magnetic resonance imaging (fMRI) to measure brain activity across networks in the brain, Johns Hopkins Medicine researchers 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 cues in areas of the brain associated with reward and cognitive control.

The study’s findings were published Sept. 28. PLOS ONE.

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

Participants were given a food word reactivity test during both scans. This test involved looking at how people’s brains responded to food words, such as menu items on a chalkboard.

To maximize the appetitive response in the brain, the 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 if they thought they should not eat that food, to see how they approached making decisions about each food.

The study also showed that stress affects the brain’s responses to food. image public domain

“Experiments showed that obese and lean adults differ slightly in brain responses, with obese adults showing less activation of cognitive control regions to food words, particularly high-calorie foods like grilled cheese,” says lead researcher Susan Carnell. , Ph.D., associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.

The study also showed that stress affects the brain’s responses to food. For example, obese individuals showed greater activation of the orbitofrontal cortex, a brain reward region, after stress testing.

“We also found evidence of links between subjective stress experienced and brain responses in both groups. For example, lean individuals who reported higher stress following the test showed lower activation of the dorsolateral prefrontal cortex, a brain area important for cognitive control,” says Carnell.

About this stress and appetite research news

Author: Marisol Martinez
Source: Johns Hopkins Medicine
Communication: Marisol Martinez – Johns Hopkins Medicine
Picture: image public domain

Original research: Open Access.
“Obesity and acute stress modulate appetite and neural responses in the food word reactivity task” by Carnell et al. PLOS ONE

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Abstract

Obesity and acute stress modulate appetite and neural responses in the food word reactivity task.

Obesity may result from excessive intake in response to environmental food cues, and stress may result in increased intake and body weight. We used a novel fMRI task to explore how obesity and stress affect appetitive responses to relatively minimal food cues (words representing food items, presented similarly to a chalkboard menu).

Twenty-nine adults (16K, 13M), 17 with obesity and 12 underweight, completed two fMRI scans, one following a combined social and physiological stressor and the other following a control task. A food word reactivity task evaluated subjective food approach (wanting) as well as neural responses to words denoting high energy density (ED) foods, low ED foods, and non-foods as well as food aversion (restriction) responses.

Each scan was followed by a multi-item ad-libitum meal. The obese and lean groups showed differences as well as similarities in activation of the appetitive and attention/self-regulation systems in response to the words food versus no food and high ED versus low ED food.

Activation patterns were broadly similar between stressful and non-stressful conditions, with some evidence for differences between conditions in both the obese and lean groups. The obese group ate more than the lean group in both conditions.

Our results suggest that neural responses to minimal food cues in stressful and non-stressful situations may contribute to overconsumption and adiposity.

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