BACKGROUND: Ghrelin is a recently discovered orexigenic gastric hormone, whose production is induced by lack of food in the stomach. In morbidly obese individuals, ghrelin levels are low compared to lean persons. During dieting, plasma ghrelin levels increase, leading to an orexigenic signal, which could explain the lack of success of dieting in morbidly obese individuals. Morbid obesity is best treated with bariatric surgery, in which gastric bypass is reported to be more effective than restrictive surgery. A possible explanation could be the difference in plasma ghrelin levels after both operations for bariatric surgery. In this study, plasma ghrelin levels were investigated during a 2-year follow-up. METHODS: 17 morbidly obese patients received gastric restrictive surgery. Plasma ghrelin, leptin and insulin levels were evaluated preoperatively and 1 year and 2 years postoperatively. RESULTS: BMI decreased from 47.5 +/- 6.2 kg/m(2) to 33.2 +/- 5.8 kg/m(2) (P <0.001). Plasma ghrelin levels were significantly increased 1 year (P <0.05) and 2 years (P <0.02) postoperatively. Fasting plasma leptin and insulin levels were significantly lower at 2 years after surgery (P <0.001). CONCLUSION: After gastric restrictive surgery, ghrelin levels increased, in contrast to the reported fall in ghrelin levels after gastric bypass. This difference in ghrelin levels between these operations may be the key to understanding the superiority of gastric bypass in sustaining weight loss compared with restrictive surgery.