An apparatus comprising: a scent storage adapted to store a first plurality of scents; a scent delivery device adapted to: deliver a first plurality of scents to an individual; a data storage adapted to store data; a processor, characterised in that the processor is adapted to: determine, for each respective scent among the first plurality of scents, an effect of the respective scent on an appetite of the individual and a duration of the effect of the respective scent on the appetite of the individual; identify a second plurality of scents that produce a particular effect on the appetite of the individual appetite based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; store data identifying the second plurality of scents; generate a delivery schedule for delivery of the second plurality of scents based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; and cause the scent delivery device to deliver the second plurality of scents to the individual in accordance with the delivery schedule to produce the particular effect on the appetite of the individual. a scent storage adapted to store a first plurality of scents; a scent delivery device adapted to: deliver a first plurality of scents to an individual; a data storage adapted to store data; a processor, characterised in that the processor is adapted to: determine, for each respective scent among the first plurality of scents, an effect of the respective scent on an appetite of the individual and a duration of the effect of the respective scent on the appetite of the individual; identify a second plurality of scents that produce a particular effect on the appetite of the individual appetite based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; store data identifying the second plurality of scents; generate a delivery schedule for delivery of the second plurality of scents based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; and cause the scent delivery device to deliver the second plurality of scents to the individual in accordance with the delivery schedule to produce the particular effect on the appetite of the individual. determine, for each respective scent among the first plurality of scents, an effect of the respective scent on an appetite of the individual and a duration of the effect of the respective scent on the appetite of the individual; identify a second plurality of scents that produce a particular effect on the appetite of the individual appetite based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; store data identifying the second plurality of scents; generate a delivery schedule for delivery of the second plurality of scents based on the determined effect and the determined duration of the effect of the respective scent among the first plurality of scents; and cause the scent delivery device to deliver the second plurality of scents to the individual in accordance with the delivery schedule to produce the particular effect on the appetite of the individual.