For those of us who find vomiting an unpleasant experience, the idea of voluntary vomiting is a little hard to grasp. But an experienced regurgitator can induce vomiting with little effort, and thinks nothing of several vomiting sessions a day. The effect on body weight varies with each person. Many bulimics have a history of weight fluctuations, usually within a range they attempt to control by vomiting. Some are overweight, but most are within a normal weight range.
Some bulimics lose weight progressively, alternating between binges and food restriction.
There are many theories of causation and a variety of treatment strategies. The concern about body image and weight control may be a symptom of the underlying biological disorder and not a cause. The idea of a recursive feeding loop, running amok, helps us to locate the irrational behavior at a primitive, addictive level. The rational concern is not just avoiding weight gain, but also avoiding the awful feelings and the depression that follows bingeing. Many bulimics have a split personality or different eigenstates.