Body Representations in Obesity

Body representation disorders have a key role in the characterization of obesity. So far, the literature consistently pointed to a negative attitudinal body image. Conversely, after reviewing the pertinent literature, it emerges that more incoherent results have been reported for the self-perceived body size. Chapter 2 tries to clarify this issue by adopting a more innovative theoretical framework (i.e., the implicit/explicit model; Longo, 2015). For the first time, we probed the implicit representation underlying position sense in obesity, reporting a similar representation to healthy weight participants. Importantly, this result shows that not all components of body representation are affected by obesity. Chapter 3 addresses another aspect of body representation that has been neglected in obesity, namely bodily self-consciousness. The Rubber Hand Illusion has been traditionally used to investigate the mechanisms underlying body awareness. Our results show that individuals with obesity have comparable subjective experience of the illusion, while the effect of the illusion on self-location is reduced. This dissociation can be interpreted as the result of a preserved visuo-tactile integration and an altered visuo-proprioceptive integration in obesity. However, in Chapter 4 we reported that individuals with obesity have a reduced temporal resolution of visuo-tactile integration, meaning that they integrated stimuli over an extended range of asynchronies than healthy weight participants. In fact, this evidence predicts that in the RHI individuals with obesity might perceive more synchronously the asynchronous stimulation, showing a greater effect of the illusion also in this condition. Nevertheless, we failed to show this pattern of results in our study with an interval of asynchronous stimulation of 1000 ms (usually adopted in the RHI paradigm). We hypothesized that smaller time-lags, which are inside the temporal binding window of individuals with obesity and outside the temporal binding widow of healthy weight participants, might not be perceived by individuals with obesity but detected by healthy weight individuals. Accordingly, a dissimilar susceptibility to the illusion should be observed. Chapter 5 investigates this issue by adopting a modified version of the RHI that enables a parametrical modulation of the timing of the stimulation. However, we could not replicate the RHI even in healthy weight participants. The possible methodological reasons for this failure are discussed. Overall, this work tries to fill some gaps in the previous literature about body representation in obesity. Moreover, our findings provide an important clue about the possible cognitive mechanisms involved in body representation disorders in obesity. However, many questions still need an answer: due to the complexity of the domain a comprehensive knowledge of the topic might be challenging. A deep understanding of obesity is fundamental to develop multidisciplinary and efficacious rehabilitative protocols. Indeed, better treatments would significantly ameliorate individuals’ well-being but also contribute to reduce the huge health costs related to obesity comorbidities.