SSpoon: A Shape-changing Spoon That Optimizes Bite Size for Eating Rate Regulation

One key strategy of combating obesity is to slow down eating; however, this is difficult to achieve due to people's habitual nature. In this paper, we explored the feasibility of incorporating shape-changing interface into an eating spoon to directly intervene in undesirable eating behaviour. First, we investigated the optimal dimension (i.e., Z-depth) and ideal range of spoon transformation for different food forms that could affect bite size while maintaining usability. Those findings allowed the development of SSpoon prototype through a series of design explorations that are optimised for user's adoption. Then, we applied two shape-changing strategies: instant transformations based on food forms and subtle transformations based on food intake) and examined in two comparative studies involving a full course meal using Wizard-of-Oz approach. The results indicated that SSpoon could achieve comparable effects to a small spoon (5ml) in reducing eating rate by 13.7-16.1% and food consumption by 4.4-4.6%, while retaining similar user satisfaction as a normal eating spoon (10ml). These results demonstrate the feasibility of a shape-changing eating utensil as a promising alternative to combat the growing concern of obesity.