Night Eating Syndrome and weight loss after Ruen-Y-Gastric Bypass Surgery

Abstract

An intriguing but understudied hypothesis is that Night Eating Syndrome (NES) includes hypothalamic pituitary adrenal (HPA) axis dysregulation. Findings regarding the impact of obesity surgery on NES are also very limited. Our study compared night eaters and similarly obese controls prior to and following Ruen Y Gastric Bypass Surgery (RYGBS) on hormonal and psychological measures associated with HPA axis dysregulation. We performed all tests at pre-op, at 2 months after surgery, and at 5 months after surgery. We sought to explore the hypothesis that HPA axis dysregulation may be present in NES, and to gather information on sequences of changes in hormones, weight, psychopathology and behavior after RYGBS. Such information on sequences of changes may allow preliminary inferences as to causal relationships. At baseline, there were 24 study candidates drawn from a group of severely obese patients, awaiting surgical treatment. 8 subjects returned for all 3 study visits, so N=8, 4 night eaters, and 4 similarly obese controls. All patients underwent standard RYGBS by the same surgeon. We administered a series of test measurements, at the 3 time intervals, following an overnight fast, including weight, serum cortisol, insulin, and glucose. We calculated BMI, and insulin resistance. Psychological scales were administered. Our results suggest that night eaters lose weight, and improve in appearance similarly to controls at 5 months after surgery. Also, at this time, insulin, insulin resistance and hunger had improved for night eaters similarly as for controls. However, we found that night eaters, in contrast to controls had a significant increase in cortisol levels at 5 months after surgery (p=.01). Also in contrast to controls, night eaters failed to improve or worsened on measures of psychopathology between 2 and 5 months after surgery. This suggests that weight loss may be a stressor for night eaters as compared with controls. It also suggests underlying hormonal and psychological pathology in NES which is resistant to improvement with weight loss. Our results support the hypothesis of a stress vulnerable HPA axis at the core of NES.