The responses of thirteen patients with bulimia nervosa and sixteen controls matched for age and weight are described following the ingestion of a carbohydrate and a calorie-free placebo mixture in simulated binges. Psychological, hormonal and biochemical parameters were measured before and at 15 minute intervals for two hours after the simulated binge.
At baseline, the bulimics were clearly more symptomatic than the controls. The control population showed a specific satiating effect of carbohydrate upon hunger ratings. Bulimic patients responed differently showing a blunting of the normal sensation of hunger and an enhanced rating for nausea.
Prolactin, growth hormone (GH) and cortisol failed to show a carbohydrate-mediated stimulation in either population. The bulimic patients showed a different pattern of GH release, but this was independent of the challenge condition. Large neutral amino acid (LNAA) levels fell following carbohydrate ingestion, but produced an increase of up to 20% in the trytophan: LNAA ratio in both bulimic patients and the control group. Thus, while this increase in tryptophan availability failed to provoke hormone release, the time course of the carbohydrated specific effect on the sensations of hunger and nausea is compatible with a mechanism based on increased tryptophan availability. The confusion of satiety with nauseas may provide a useful focus for the future treatment of patients with bulimia nervosa.