Why do anorexia patients feel 'fat' ?
There is a measurable deviation in how patients interact with their environment.
A lot of research is currently being done into why people who are very slim not always experience this as such.
One of our research projects at Utrecht University involved, among other things, asking female participants (with and without anorexia) to walk through openings of several different widths.
ANOREXIA PATIENTS UNCONSCIOUSLY BEHAVE LIKE FATTER PEOPLE
The results showed that anorexia patients already made a quarter of a turn for openings they could easily pass through by walking forward. So without realising, the patients behaved like fatter people.
The way you move is arranged by your brain, without you realising it. Your brain has a blueprint of your body size. Based on that, the brain decides which movements can and cannot be made (such as whether or not you can fit through a narrow tunnel).
THE BRAIN USES A 'BLUEPRINT' OF THE BODY THAT IS TOO FAT
An anorexic human's brain probably bases all movement on the blueprint of a body that is fatter than the actual body. As a result, patients keep getting signals from their brains that they are too wide to carry out certain movements.
The persistent feeling of being too fat turns out to be more than 'just' a thought. There is a measurable deviation in how patients interact with their environment.