The eating behavior of 49 obese and 47 normal weight controls of both sexes was compared in laboratory. A universal eating monitor according to the Kissileff-instrument was used to obtain cumulative intake curves with chocolate pudding as laboratory food. Compared to controls the obese had a significantly higher initial eating rate (p<.002), larger spoonfuls (p<.005), and a greater total intake (p<.03) for the laboratory food. For initial eating rate a significant sex x weight interaction was found (p<.04). Higher values for males emerged only for overweight, but not for normal weight subjects. On the one hand, these data suggest an eating behavior of obese, which will promote a high energy intake in the natural environment. On the other hand, the observed differences can also be interpreted as a consequence of cognitive factors, impacting the eating behavior of obese under specific conditions.