•The mere act of preparing food increases liking and consumption.•Labor changes the sensory experience of food.•Preparing food could facilitate overconsumption. Research has demonstrated that people like and overvalue objects that they have created themselves. In the present study, whether preparing food increases the liking for and consumption of food was examined. Participants (N=60) tasted a high-calorie milkshake that was either self-prepared or other-prepared, i.e., prepared by the experimenter. The self-prepared milkshake received higher liking ratings than the other-prepared milkshake. In addition, participants who prepared the milkshake themselves consumed a larger quantity of the shake. Further analyses indicated that this effect was mediated by liking; thus, participants consumed more of the self-prepared shake because they liked it more. We refer to this phenomenon as the “I cooked it myself” effect. In sum, the study demonstrates that the mere act of preparing food could facilitate the overconsumption of high-calorie foods and provides preliminary information that may guide the design of future experiments on food preparation and consumption.