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Stress May Drive Obesity Epidemic

weightA new research study finds that some subjects consume calorie-rich foods at a significantly higher level when chronically exposed to a psychologically stressful environment.

The behavioral impact of stress and weight gain occurred among subjects who were assuming subordinate roles in their social hierarchy.

Because the relationship between diet, psychological stress and social and environmental factors is complex, researchers set out to determine whether individuals chronically exposed to psychologically stressful environments over consume calorie-rich foods.

Scientists at at the Yerkes National Primate Research Center, Emory University, found socially subordinate female rhesus macaques over consume calorie-rich foods at a significantly higher level than do dominant females.

The study, which is available in the online edition of Physiology and Behavior, is a critical step in understanding the psychological basis for the sharp increase in obesity across all age groups since the mid-1970s.

The study also is the first to show how food intake can be reliably and automatically measured, thus identifying the optimal animal model and setting for future obesity studies.

To do this, they studied the feeding patterns of socially housed female rhesus macaques, which are organized by a dominance hierarchy that maintains group stability through continual harassment and threat of aggression. Such structure is a constant psychological stress to subordinates.

During the study, female macaques were given access to a sweet but low-fat diet and a high-fat diet for 21 days each. For a 21-day period between each test diet, the group was able to access standard monkey chow only.

To track feeding patterns, automated feeders dispensed a pellet of either the low-fat or high-fat chow when activated by a microchip implanted in each female’s wrist.

Researchers found socially subordinate females consumed significantly more of both the low-fat diet and the high-fat diet throughout a 24-hour period, while socially dominant females ate significantly less than subordinate animals and restricted their feedings to daytime hours.

This difference in feeding behavior resulted in accelerated weight gain and an increase in fat-derived hormones in subordinate females. Dr. Wilson believes this may suggest profound changes in metabolism and the accumulation of body fat.

“Subordinates may be on a trajectory for metabolic problems. As this study shows, they prefer the high-fat diet and, as a result of the stress of being a subordinate, they have higher levels of the hormone cortisol.

This may be involved in the redistribution of fat to visceral locations in the body, something that is clinically associated with type II diabetes metabolic syndrome,” continued Dr. Wilson.

Using Yerkes’ extensive neuroimaging capabilities, Dr. Wilson and his research team next will attempt to determine the neurochemical basis for why subordinate females overeat; specifically, whether appetite signals and brain areas associated with reward and satisfaction differ between subordinate and dominant females.

Source: Emory University

Stress May Drive Obesity Epidemic

Rick Nauert PhD

Rick Nauert, PhDDr. Rick Nauert has over 25 years experience in clinical, administrative and academic healthcare. He is currently an associate professor for Rocky Mountain University of Health Professionals doctoral program in health promotion and wellness. Dr. Nauert began his career as a clinical physical therapist and served as a regional manager for a publicly traded multidisciplinary rehabilitation agency for 12 years. He has masters degrees in health-fitness management and healthcare administration and a doctoral degree from The University of Texas at Austin focused on health care informatics, health administration, health education and health policy. His research efforts included the area of telehealth with a specialty in disease management.

APA Reference
Nauert PhD, R. (2015). Stress May Drive Obesity Epidemic. Psych Central. Retrieved on August 15, 2018, from https://psychcentral.com/news/2008/05/14/stress-may-drive-obesity-epidemic/2286.html

 

Scientifically Reviewed
Last updated: 6 Oct 2015
Last reviewed: By John M. Grohol, Psy.D. on 6 Oct 2015
Published on PsychCentral.com. All rights reserved.