Plain language summary
Binge Eating Disorder (BED) is characterised by eating a large quantity of food (objectively) at least 2 times a week for 6 months, and is associated with a loss of feelings of self control. It is found it around 30% of obese individual who participate in weight loss programs. There may be a biological element to this disorder with possible mechanisms including heritability, an enlarged stomach capacity and genetic mutations. Hormones may also play a role in BED. This study aimed to establish whether obese individuals had higher fasting and post feeding ghrelin levels, and slower gastric emptying compared to a non-obese BED control group. 38 overweight and obese women were recruited and classified into one of three groups; non binge eaters (12), binge eaters but not meeting full BED criteria (14) and BED syndrome (11). 10 of the 11 BED women were randomly allocated to a 6 week treatment of either a) cognitive behavioural therapy (CBT) and a diet or b) a non treatment wait-list control. The study found that the BED women had a lower fasting ghrelin level and that ghrelin also declined less after a meal for this group. The authors stated that this appeared to be counterintuitive because ghrelin (which stimulates hunger) was expected to be higher for overweight and obese people. They suggest that binge eating may down-regulate ghrelin and be a response to over-eating (often when not hungry). They also suggested that ghrelin declining less for overweight and obese BED women may suggest that the magnitude of the ghrelin fall may be linked to higher satiation (so they have lower satiation and continue eating compared to other individuals).
Abstract
Binge-eating disorder (BED), characterized by binge meals without purging afterward, is found in about 30% of obese individuals seeking treatment. The study objective was to ascertain abnormalities in hormones influencing appetite in BED, especially ghrelin, an appetite-stimulating peptide, which was expected to be elevated. Measurements were made of plasma insulin, leptin, glucagon, cholecystokinin, and ghrelin, as well as glucose following an overnight 12-h fast, prior to and after ingestion (from 0 to 5 min) of a nutritionally complete liquid meal (1254 kJ) at 0830 h, at -15, 0, 5, 15, 30, 60, 90, and 120 min. Appetite ratings including hunger and fullness were also obtained. An acetaminophen tracer was used to assess gastric emptying rate. Three groups of comparably obese women (BMI = 35.9 +/- 5.5; % body fat = 44.9 +/- 4.7) participated: 12 nonbinge eating normals (NB), 14 subthreshold BED, and 11 BED. The BED subjects, compared to NB subjects, had lower baseline ghrelin concentrations prior to the meal, a lower area under the curve (AUC), with lower levels at 5, 15, 30, 90, and 120 min, and a smaller decline in ghrelin postmeal (all P < 0.03). The other blood values did not differ among groups, and neither did gastric emptying rate nor ratings of fullness. The BED subjects were then randomly assigned to treatment with cognitive-behavior therapy and diet (n = 5) or to a wait-list control (n = 4). Baseline ghrelin (P = 0.01) and AUC increased (P = 0.02), across both conditions, in which most subjects (7 of 9) stopped binge eating. The lower fasting and postmeal plasma ghrelin levels in BED are consistent with lower ghrelin levels in obese compared to lean individuals and suggests downregulation by binge eating.
