| Obesity, a spreading epidemic in the U.S., is often associated with negative health consequences. Approximately, 20–30% of those who seek treatment for obesity are binge eaters. As a distinct obesity subgroup, these individuals may have unique treatment needs. Obese binge eating (OBE) is characterized by the consumption of large quantities of food over a short period of time, loss of control over eating, and a failure to perceive satiation. Current evidence supports a theoretical model that operationalizes OBE as a primary biological satiation defect associated with alterations in several neurochemicals (corticosterone, insulin and opioids) thought to influence satiation.; The obese Zucker rat (OZR) exhibits a hyperphagic eating pattern similar to the OBE and this model was used to examine the relationship among these altered neurochemicals and satiation (meal size). Using an experimental design, a kappa opioid receptor antagonist, nor-binaltorphamine (N-BNI), known to influence food intake, corticosterone (CORT), and insulin levels, was injected into the lateral ventricle of the brain of OZR (n = 11), while a control group (n = 2) received a saline injection. Over 2 weeks, meal size and frequency was assessed continually with computerized real-time monitoring equipment, while total intake and body weight were measured daily; plasma for CORT and insulin levels was obtained at intervals. Cumulative food intake over the largest meal of the day was examined with curve estimation for a food intake pattern of satiation.; Two distinctive responses emerged. Some subjects responded to central injection of N-NBI with a reduction in body weight and food intake (responders); others exhibited a lesser response (poor responders). Repeated measures ANOVA showed a significant decrease in body weight (p = .001) and food intake (p = .03) in responders, when compared to poor responders and controls. Satiation was influenced to a greater extent in responders who showed a reduction in meal size and a rate of intake slowing over the largest meal of the day indicating building satiation. There were no significant reductions in CORT and insulin levels.; Greater understanding of the biological mechanisms that regulate ingestive behavior and weight maintenance are critical to finding effective biobehavioral nursing interventions for binge eating and weight loss. |
