Background: An enhanced gastric emptying rate might reduce the satiating effect of food and thereby promote obesity. Gastric emptying rate has previously been compared between obese and lean subjects with conflicting outcome.
Objective: Comparison of gastric emptying rate in lean and obese subjects before and after a major weight reduction.
Design: The study was designed as a case-control study comparing obese and lean subjects and a subsequent comparison of obese subjects before and after a dietary induced major weight reduction.
Method: Gastric emptying rate following a solid test meal was estimated scintigraphically for 3 h using the left anterior oblique projection.
Subjects: Nineteen non-diabetic obese (mean BMI=38.7 kg/m2) and 12 lean (mean BMI=23.1 kg/m2) males matched for age and height. All obese subjects were re-examined after a mean weight loss of 18.8 kg (95% CI, 14.4-23.2) achieved by 16 weeks of dietary intervention followed by 8 weeks of weight stability.
Results: When comparing obese and lean subjects no differences were seen in overall 3 h emptying rate (30.3% per hour vs 30.5% per hour). However, a trend towards a higher percentage gastric emptying during the initial 30 min was seen in the obese when compared to lean subjects (24.0% vs 17.8% of the test meal; P=0.08). Weight loss was associated with a reduction in percentage gastric emptying during the initial 30 min (from 24.0% to 18.3% of the test-meal; P<0. 02), whereas the overall 3 h emptying rate was unaffected (30.3% vs 30.9% per hour). Neither initial or overall emptying rate differed between reduced-obese and lean subjects.
Conclusion: Overall 3 h gastric emptying rate was similar in obese and normal weight males, and unaffected by a major weight loss. However, percentage gastric emptying during the initial 30 min for a solid meal appeared to be increased in obese males and was normalized after a major weight reduction.