One function of the stomach is as a reservoir for food; hence, the stomach's capacity may limit the amount of food ingested. A stomach with a large capacity has been associated with bigger test meals. We compared the stomach capacity of three groups of women: normal (n=10), obese (n=11), and bulimic (n=10). Following an overnight fast, gastric capacity was estimated by filling a gastric balloon with water at 100 ml/min, with pauses for measuring intragastric pressure. One estimate was based on the maximum volume the subject could tolerate as indicated by a maximal rating of abdominal discomfort. Another estimate was based on the volume required to produce a given rise of intragastric pressure, 5 cm H(2)O. A third related measure was based on a maximal rating of fullness. Based on these estimates, the gastric capacity of the bulimics was the largest, with the obese subjects intermediate. We then separated the obese subjects according to whether they reported binge eating (n=6) or not (n=5). The gastric capacity of the binge-eating subset was similar to the bulimics, and the nonbinge-eating subset was similar to the normals. Thus, gastric capacity appears more related to binge eating behavior than to body weight.