Do subjects with obesity underestimate their body size? A Narrative review of estimation methods and explaining theories

The widespread of overweight and obesity in the developed countries is a real societal issue, nevertheless a considerable amount of subjects with obesity do not recognize their condition. Researchers used different methods to assess body size perception by obese subjects and the results show that while some subjects with obesity estimate accurately or overestimate their body size, others underestimate their weight and their body size measures. A failure to identify overweight or obesity has serious consequences on the subject’s health, as it is widely recognised that self-awareness is the first step to engage in a rehabilitation program. The spread of obesity underestimation and its implications make the case for a new hypothetical body image disorder, which has been called Fatorexia™. It consists in the significant underestimation of body size by subjects with obesity, as they are unable or unwilling to acknowledge their condition. Some researchers proposed a social explanation to the underestimation phenomenon, but here an alternative hypothesis, the Allocentric Lock Theory (ALT), is outlined to describe the mechanisms behind the underestimation of body size by subjects with obesity.