Effect of obesity and major weight reduction on gastric emptying

BACKGROUND: An enhanced gastric emptying rate might reduce the satiating ef fect of food and thereby promote obesity. Gastric emptying rate has previou sly been compared between obese and lean subjects with conflicting outcome. OBJECTIVE: Comparison of gastric emptying rate in lean and obese subjects b efore 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 afte r a dietary induced major weight reduction. METHOD: Gastric emptying rate following a solid test meal was estimated sci ntigraphically for 3h using the left anterior oblique projection. SUBJECTS: Nineteen non-diabetic obese (mean BMI=38.7kg/m(2)) and 12 lean (mean BMI=2 3.1kg/m(2) males matched for age and height. All obese subjects were re-exa mined after a mean weight loss of 18.8kg (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 3h emptying rate (30.3% per hour vs 30.5% per hour). However, a tr end 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 percent age 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 differe d between reduced-obese and lean subjects. CONCLUSION: Overall 3 h gastric emptying rate was similar in obese and norm al 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 mates and was normalized after a major weight reduction .