The amount of food ingested was measured in 12 non-obese volunteers after preloads with glycerol, glycose, and water, administered in a double-blind design. A palatable soup was served in concealed containers and on different plates and the volume, consumed on each occasion, was registered. Administration of 7.5 g glycerol 20 min before the meal reduced the mean energy intake by about 10% compared to both an equicaloric amount of glucose solution or the same volume (30 ml) of water. At the start of the meal 20 min after the preload, the plasma glycerol concentration was about 10 times higher than base-line values. The free fatty acid/glycerol ratios did not correlate to the reduction of energy intake.