Stud Health Technol Inform. 2013;184:356-62. From Body Dissatisfaction to Obesity: How Virtual Reality May Improve Obesity Prevention and Treatment in Adolescents Giuseppe RIVA 1-2 , Andrea GAGGIOLI 1-2 , Antonios DAKANALIS 3 1 Applied Technology for Neuro-Psychology Lab, Istituto Auxologico Italiano, Milan, Italy 2 Psychology Department, Catholic University of Milan, Italy 3 Psychology Department, University of Pavia, Italy Abstract. Different studies, including longitudinal studies, suggest a link between body dissatisfaction, unhealthful weight-control behaviors and obesity in both male and female adolescents. In this paper we suggest that body dissatisfaction in obese adolescents may be driven by an allocentric negative body image that is no more updated by contrasting egocentric representations driven by perception. In other words, subjects are locked to an allocentric negative representation of their body (allocentric lock hypothesis - http://dx.doi.org/10.1016/j.mehy.2011.10.039) that their sensory inputs are no more able to update even after the dramatic body changes following a successful diet. More, the possible role of virtual reality in the prevention and treatment of this disorder is presented and detailed. Keywords: Obesity, Adolescence, Body Dissatisfaction, Allocentric Lock Hypothesis 1. Introduction Most clinicians and patients consider adolescent obesity just as a problem of energy balance: more energy input than expenditure. So the suggested ways to cope with it are quite simple: more physical exercize and healthier food. For example, the First Lady Michelle Obama, presenting her prevention program “Let’s Move” underlines [1]: “Since we launched Let’s Move!, we’ve made significant progress—from providing our kids with healthier food and greater opportunities for physical activity in school and in their communities, to getting families the information they need to make healthier decisions, to ensuring that more people have access to healthy, affordable food.” (p. 1). Neverheless, clinical practice presents a more complex picture of the problem. On one side, the typical prevention programmes based on these strategies are not successful in the long term. For example, in the same issue of the “Childhood Obesity” journal including the First Lady paper, Yin and colleagues discussed the impact of a 3- year after-school obesity prevention program in elementary school children [2]. Their conclusions is that the program, even if effective in the short term, was not able to modify permanently the behaviors of the children: “The rebound effect due to program discontinuity during the summer breaks, which has been shown by others, is