DEVELOPING A MODEL OF STRESS-INDUCED OBESITY

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This study is designed to develop procedures to better understand the neural mechanisms for the ingestion of comfort foods. The notion that the ingestion of calorically dense comfort foods to relieve socio-environmental stressors contributes to the obesity epidemic is gaining acceptance. Monkeys are housed socially and those of subordinate social status show behavioral and endocrine indices of stress. Females had a computer chip implanted subcutaneously in the wrist that, when reaching into an automated feeding dispenser would identify the monkey and deliver one pellet of food. In this way, food intake was monitored 24 hours per day, seven days a week. In the final year of the project, we showed that when given a choice between the typical low fat, high fiber monkey diet (LCD) and a diet high in fat and sugar (HCD), dominant females prefer the HCD but continue to eat the LCD as well. Subordinates too preferred the HCD but consumed nearly twice as many calories during the choice condition as did the dominant animals. When the choice was removed, subordinates continued to come significantly more calories of the less preferred LCD. Behavioral studies indicated that upon the removal of the HCD data, anxiety-like behavior increased significantly. Finally, consumption of the HCD actually increases rather decreases stress hormone responsiveness. These studies are providing insights into how socio-environmental variable may contribute to excess food consumption and obesity in humans.