Reduced stomach capacity in obese subjects after dieting.

The objective of the study was to assess the change in gastric capacity of obese subjects consuming a hypoenergetic diet. Otherwise healthy, obese subjects participated in a prospective controlled study as hospital outpatients. Fourteen (11 females, 3 males) subjects were assigned to the diet group and 9 (7 females, 2 males) were assigned to the control group. Subjects in the diet group were provided a 2508-kJ/d(600 kcal/d) formula diet for 4 wk. Subjects in the control group ate ad libitum for 4 wk. Gastric capacity was determined before the study and 4 wk later by oral insertion of a latex gastric balloon after an overnight fast. The balloon was infused with water at a rate of 100 mL/min, with pauses for measuring intragastric pressure, until no further distension was tolerated. Two indexes for estimating gastric capacity were used based on subjective and objective criteria: 1) the maximal volume that could be tolerated, and 2) the volume required to produce a rise in water pressure of 5 cm. Subjects in the diet group, who lost a mean of 9.1 kg, showed a 27% reduction in gastric capacity based on the first index (P = 0.004) and a 36% reduction based on the second index (P = 0.006). For the control subjects, gastric capacity did not change significantly with use of either index. The results demonstrate a reduction in gastric capacity in obese subjects after a restricted diet.