Appetite Hormones in Binge Eating Disorder

The objectives are to study appetite-related hormones regulating food intake under normal conditions and following a stressor in the morning and evening (when most binge episodes occur), to help reveal biological mechanisms in BED. We plan to enroll: 32 obese Ss with BED (16m, 16f), 32 obese Ss without BED (16m, 16f) and 32 normal-weight Ss without BED (16m, 16f). Height, weight, waist circumference, and body fat will be assessed during a first appointment. On two different days separated by at least a week, Ss will ingest a fixed liquid meal once in the morning and once in the evening. Appetite ratings and collections of blood and saliva to measure hormones will continue for 2 hours after the fixed meal. This will be followed on each day by a laboratory stress protocol (Socially Evaluated Cold Pressor Test; SECPT), and then consumption of an ad libitum meal 30 minutes later. On one day during the protocol, the participant will collect saliva using a swab immediately after waking and again at 08.00. In order to capture more naturalistic eating episodes, all Ss will additionally record food intake, rate appetite, and measure salivary cortisol before and after one evening meal, and one after-dinner snack (or after-dinner binge for BED Ss). On two additional days, we will use fMRI to assess brain activation in response to high-palatability food (HPF) relative to low-palatability food (LPF) or non-food (NF) visual cues following the SECPT and a control condition using warm water. On each day, following the fMRI scan, an ad libitum meal will be consumed.