We previously fed rats with an ester (90 ppm in a powdered AIN93G diet) synthesized from gallic acid and 1,2-dioleoyl glycerol and found that it promoted weight loss more effectively than either octyl gallate or gallic acid. Here, we esterified ferulic acid (FerA) with oleic acid, monooleoyl glycerol and dioleoyl glycerol to obtain oleoyl ferulic acid (FO), feruloyl monooleoyl glycerol (FMO) and feruloyl dioleoyl glycerol (FDO) esters, respectively. A mixture of AIN93G and 90 ppm of each ester and FerA was fed to 10-week-old male Wistar rats for 12 weeks. The FMO and FDO groups weighed less than the control group starting from approximately 16 weeks of age. At 21 and 22 weeks of age, weight significantly differed between the FMO and both groups, respectively, and controls. The FO, FerA and control groups did not significantly differ in terms of body, liver, kidney and retroperitoneal fat tissue weights and serum biochemical findings. We concluded that the hydroxyl group of FerA is essential for promoting weight loss and that the carboxyl group should be esterified with alcohol. In addition, monooleoyl glycerol and dioleoyl glycerol did not show any difference as the alcohol moiety of the ester in the weight loss effect.