The role of the stomach in regulating appetite in bulimia nervosa was examined. Subjects were nine normal and nine bulimic women of similar age, height, and weight. Gastric capacity was estimated by filling a balloon in the stomach. The mean stomach capacity of bulimic subjects was significantly larger than that of normal subjects, as revealed by the larger balloon volume tolerated (P less than 0.01) and by the larger volume needed to produce a 5 cm H2O increase in intragastric pressure (P = 0.07). The intake of a liquid meal was also significantly larger for the bulimic subjects. Gastric-emptying rate of a liquid meal was significantly delayed in the bulimic subjects during the initial 5-15 min. In all subjects, test-meal intake correlated significantly with gastric capacity (r = 0.53). In the bulimic subjects, self-reported binge intake (J) also correlated significantly with gastric capacity (r = 0.75). Binge eating in bulimic subjects may enlarge gastric capacity, which could then promote even larger binges through positive feedback.

Cholecystokinin (CCK) may affect food intake by augmenting neural activity from the distended stomach, thereby amplifying satiety signals. To test the hypothesis that subjects would report more fullness and less hunger with gastric distension when CCK-8 (112 ng/min) was infused than when saline was infused, a gastric balloon was inflated in the stomachs of four women. When the balloon was inflated to 500 ml, there was no difference in gastric pressure between the CCK-8 and saline conditions. Nonetheless, ratings of fullness were higher with CCK-8 administration. When the balloon was inflated to the maximum volume tolerated, the pressure rise was significantly smaller with CCK-8 infusion. In addition, fullness ratings rose and hunger ratings declined more steeply in relation to gastric pressure when CCK-8 was infused. In all conditions, gastric contractions were practically abolished with CCK-8 infusion. CCK-8 relaxed the stomach and concurrently sensitized the subjects to gastric pressure.

To determine its efficacy and safety in treating obesity, a silicone-rubber balloon was passed into the stomach of 10 nondieting, obese subjects. In a counterbalanced sequence, the balloon was inflated with 400 mL for 1 mo and deflated for 1 mo. Lower intakes of solid and liquid test meals (NS), significantly slower gastric emptying, and concomitant changes in glucose, insulin, glucagon, and cholecystokinin concentrations consistent with slower emptying resulted during balloon inflation. After balloon inflation, one small gastric ulcer developed, which subsequently healed. Significant weight loss occurred during the second and third week of the inflation period (F[1,9] = 5.0, p less than 0.05). However, the weight loss was small and the significant effect did not continue through the fourth week.

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