Anorexia means loss of appetite. But there is disagreement about whether the appetite is changed by the disease anorexia nervosa (AN). Appetite is a subjective essential sense, which is regulated in a complex ensemble between brain, stomach - intestinal system and hormones. As a direct result of malnutrition, there are many somatic complications caused by the disease AN. Several of these complications may in itself affect hunger- and satiety perception. An example of this is delayed gastric emptying. Furthermore, changes in the hormone systems affects the biological "reward system" in the brain, which plays an important role in appetite regulation. There is clearly need for research that could lead to better treatments for AN. Hunger- and satiety perception has only been studied in a few small cross-sectional studies with no clear conclusion.