In a study published in the American Journal of Clinical Nutrition, (1997) Allan Geliebter and colleagues from Columbia University College of Physicians and Surgeons reported their data of obese patients who took a 600 calorie diet for 4 weeks.

Patients were studied before and after the 4-week test period with a stomach balloon measuring device. The researchers found that the obese dieters had a 27% reduction of the measured size of their stomachs, while loosing an average of 9.1 kg (18.2 lbs). Furthermore, obese dieters felt the sensation of stomach fullness at a 36% smaller stomach capacity than nondieters.

These results indicate not only that the size of the stomach does shrink in obese dieters, but also that the dieters felt full with smaller volumes of food after dieting.

The authors add that it is probably not the obesity state itself that enlarges the stomach, but rather the overeating associated with the obesity. For example, they point out that they have found enlarged stomachs in normal weight bulimic subjects (persons with binge eating disorder). They attribute this finding to the effect of repeated ingestion of large individual meals rather than total daily intake.

The authors further point out that the enlarged stomach capacity in obese individuals may actually contribute to overeating. They suspect that the nerve sensors of stretch (that would indicate fullness to the brain) in these stomach do not become activated without greater food volumes.