Most prosthetic foot products are adjusted by skilled prosthetists using a variety of gait analysis and information given to them by patients in terms of feel and experience. The design of prosthetic foot has traditionally focused on optimising stiffness to support the body weight and storage/release mechanisms of strain energy from heel contact to push off. As a result of this, the optimisation process of a prosthetic foot is simple and sometimes insufficient. It is proposed that the stiffness and energy release mechanisms of prosthetic feet be designed to satisfy amputee’s natural gait characteristics that are defined by an effective roll-over shape and corresponding ground reaction force combinations. Each point on the roll-over shape is mapped with a ground reaction force corresponding to its time stamp. The resulting discrete set of ground reaction force components are applied to the prosthetic foot sole and its stiffness profile is optimised to produce a desired deflection as given by the corresponding point on the roll-over shape. The robustness of this novel computational method is tested on three prosthetic designs. The mesh sensitivity results and the discretisation error resulting from applying finite number of ground reaction forces are discussed. It is shown that the proposed methodology is able to provide valuable insights in the guidelines for selection of materials for a multi-material prosthetic foot.